Good Contents Are Everywhere, But Here, We Deliver The Best of The Best.Please Hold on!
+01 (414) 230 - 5550

Started by a group of passionate developers as an internal event in 2013, Haxorz now become an Unconference focused on software craftsmanship, agile practices and innovative management.

Haxorz at Selleo is a part of an internal day we hold once a month. Started by a group of passionate developers in 2013, Haxorz now became an Unconference focused on software craftsmanship, agile practices and innovative management. And yes it is open for everyone.
The idea of Haxorz looks simple—sharing knowledge with other colleagues. Most talks are held in English, but you’re not forced to do that—if you don’t feel confident enough, presenting something in Polish is better than not presenting anything at all.

If you’re wondering how many advantages it has, let me list some of them.


Honing English.

As software developers we work with clients all around the globe and it means that the whole communication is held in this contemporary lingua franca.


Learning how to sell something.

Presenting is more than selling ‘a real product’. It means selling your ideas, concepts, solutions. Every time you try to encourage someone to do something, you’re selling your idea, or a piece of advice.


Do the above in a smaller scale.

If you have a dream or a goal to give a speech to millions of people, you’d better start small, or you rather fall. Seriously.


New formula

Today during our Feedback360 session I realized that most ideas, solutions and good practices we implemented here, at Selleo, are hardly known to the ‘outside’ world. We should spread them in order to give something back to the community we live and operate in.

This is way Haxorz became open, and we’ve been successful! Apart from guys from Selleo, we had 12 guests that could take part in our unconference. All in all there were more than 30 people—number that often exceeds more regular meet-ups.


Presentations and the curse of knowledge

Most people think that there’s no point in sharing something as ‘everyone knows it’ and ‘it’s obvious’. That’s the curse.If you’re wondering how many advantages it has, let me list some of them.

Arek Janik presentation about common CSS pitfalls made me realize that guys more into the backend do common mistakes that front-end ones don’t. Even though ‘it was obvious’ some people could benefit from his presentation and, down the road, make him spend less time to fix some broken layouts.


At Selleo people thrive in an environment where nurturing your skills and habits is a standard. We want to progress as individuals and as a team. We play to the same goal.

Darek Wylon presentation about giving a feedback to other people reminded me that nowhere in the past I had a chance to learn how to do it. Schools don’t teach it. In most companies ‘making a mistake’ is a kind of a deadline, labelling you as a man failure. Giving feedback is a skill one has to learn and today’s Haxorz was, I hope, a chance to show our guests how to do that in the right way.

There were also , more technical presentations. One about Rails by Tomasz Noworyta when he told us about challenges connected with internalization and metrics systems on the global project. We also had a chance to listen to Radosław Jędryszczak presenting how to do pair programming effectively and Bartłomiej Danek showing how to document the project to make customer happy.

Working in an agile environment I didn’t cover all the details, missed some points, but let’s face it—this article is done the same way as Haxorz is–by continuous improvements and learning by mistakes.


Last but not least.

After Haxorz our guests had a chance to participate in networking part, visiting our offices and also could see how we work on a day to day basis trying to bring some value to the city we’re operating in and community we have common ideas with.


Geeks, Ireneusz Skrobiś

On the 12th of December, Bartłomiej WójtowiczTomasz Czana and Jarosław Kisiołek organized 4th edition of Day With Board Games. They brought more than 20 titles including Selleo’s favourites: 7 WondersSurvive: Escape from Atlantis!Love LetterKing of TokyoPuerto RicoDixitTicket to RideColt ExpressExplodnig KittensSplendorPandemic and many more (here you can find some photos of us playing those games).

Another attendance record has been established with 24 participants (6 more than last edition). As usual, beside playing games we ate a lot of pizza, drank a lot of soda and we had a really good time together. Unfortunately 10 hours passed by way too fast so I hope that next edition will be organized really soon.



Do you remember the days of sitting in a library (I mean a place, not a piece of code!), flipping through books and encyclopedias in order to prepare homework that your teacher gave you? I did and actually it wasn’t that bad. However the Internet gave us access to the best, often community-driven resources with tools that could enhance the chance of remembering and learning to a greater extent. Let me guide you through how you can maximize learning and still have good memories about your teachers! Studying any field topic has never been so easy and accessible. Now, in the information era, all knowledge is accessible a few strokes away. It doesn’t, and in fact, shouldn’t mean that you can replace your memory with Google Apps. Putting aside, that you should also disconnect from the Internet and sift through the massive amount of information, knowledge worth thousands (if not millions) is a low-dangling fruit. Do you want to eat it? Learn how it may be even more palatable!


Computer never gets tired. Only you do.

A few days ago, I finished the whole Rails Path in CodeSchool. Sometimes I got stuck, but the constant feedback I got after submitting the answer, gave me more insight to what was wrong. If the error wasn’t too specific, I could have a closer look, look it up, or try to use what would work, but Code School didn’t accept this as an answer. This is of course a disadvantage as any course app has a limit to possible answers. After every ‘failure’, I wasn’t punished, or forced to stand in the corner and kneel on the bag of peas (just joking if you are wondering). Instead the forgiving interface gave me some hints as to what is wrong and how I could finish the level. Since March 2014 we started using Code School in Selleo as another learning tool enabling every colleague to perfect his craft, and as a part of the mentoring of new developers. Personally I am very fond of using Code School and find it a great source to keeping me moving forwards.

Everywhere in your pocket.

It’s not surprising, that our mobile phones have become more powerful than the PC’s that we had in 2000, but one story really struck me. According to the book  ‘The way of linguist’ , Steve Kauffman, the author, tells the story of how he was learning Chinese with a large tape recorder, not portable in any possible way. Comparing it to todays devices he was right that we can learn any language, any time, and that there should be no excuses about this or that. Any modern mobile phone you have in your pocket can serve as a learning tool whilst commuting or anytime you may have a spare window time. Instead of wasting most of your time playing games, surfing the Internet, consider using apps that can bring more value, even if the amount of time you can spend in these time windows is as short as 15-20 minutes. Remember that it is the time that matter, and every minute adds up! If your dream is to work as a developer, consider using mobile apps for such online courses as Coursera, or  Railscasts. Another type of apps that will serve as a brain workout is Lumosity (60 million accounts!), or any maths games. Truth be known, the only skill you have to develop (in any field) is active fluency in English. If the above examples don’t convince you, for example watching TED talksCrash Course episodes and the like on the bus (or any way of commuting) will make your trip not only pleasant but will give a great start to the day and stimulate your mind! Remember, time flies!


In 1980s Piotr Wozniak, a Polish scientist, created SuperMemo based on his studies of the forgetting curve. Though a manual technique was widely used years before via paper cards, only a computer-based app was able to calculate the best time to review the already learnt material. In short, Spaced Repetition System (the SRS) is a technique, that helps you recall things, to not forget them in the long term. Imagine that you’re learning Polish and there’s a word ‘apple’ on the screen and you have to guess the Polish translation. If you answered ‘Jabłko’ (before pressing the button to show answer), the app can schedule your next review in 2 days. If you answer correctly then, it can, for example, schedule next review in 4 days, and so on (actually the algorithm is far more complex). There are at least two rules in order to make the best out of the SRS technique. The first, is that you have to understand (or relate it to something you have an experience with), and to do reviews on a daily basis, possibly at the same time of the day. Using SRS is not only effective in language learning (try Anki, or any SuperMemo course). In fact many people use it to study maths, poems and keyboard shortcuts. I was surprised that ShortcutFoo started to use it to help you to master Vim or any other editor. Unfortunately, the authors forgot about keeping it simple and in most cases it is not how it should be implemented. Apple – Jabłko – Apple – that’s obvious. But it took me some time to win the fight in which I had to type `T-w` after reading ‘move before previous W in the line` – what?! In SRS the idea is that it shouldn’t take you long to respond. It should be automatic, become a habit and be obvious. Reading ‘Practical Vim’ I learnt that I can edit text at the speed of thought. The example I have given above is contrary to how Vim works. It is as if you were learning English this way: (you want to say ‘I go to school every day’)


  1. I – after ‘I’ I have to use verb in with or without ending ‘s’, so
  2. go – now I have to use noun and preposition, so
  3. to school – should I add adverb at the beginning or at the end? What about ending ‘-s’?
  4. every day

It’s the other way around. In reality you’re not learning a language, you acquire it, immerse yourself in it or you are exposed to it. Sadly, the example above is the way that most of us learn (if you wondering I barely passed the Matura exam and could not speak a word after finishing high school!). Only a few of us had the chance to meet a passionate teacher, who knew that language is all about communication, not about tests, grammar or learning how to pass this or that exam! Anyway, I found ShortcutFoo very interesting. Simon, my colleague that sits (or stands) next to me, is my opponent in Vim fights. A single fight (or even sometimes three in a row) may not only  be a good refresher when you’re stuck with some prob… (challenge ;), takes 3 minutes, but it’s definitely better than watching funny videos on YouTube.

Rich & vivid content

Close your eyes and imagine you’re sitting in the library studying the CSS box model from W3C spec. There are only few people around, each one of them focusing on something, tapping on the desk from time to time. The sound of the pendulum clock ticking is as only as loud as it was in the middle of the night. 20 minutes after you have had your lunch, yawning and sipping the awfully bad coffee from the coffee machine, your head begins to nod, but you have to remember this: “The CSS box model describes the rectangular boxes that are generated for elements in the document tree and laid out according to the visual formatting model.” Remember: there are no images, figures, unicorns or candies. Now consider this. Forget about closing your eyes this time unless you have some awesome text-to-speech app – Siri or something for 200 dollars. This example will make you feel at home. It’s Saturday, in second or third week of Spring. The temperature is mild, air crisp, and after a morning jog returning home you can even smell the fresh smell of the curtains and other nice scents after the spring clean. Having had breakfast, full of fruits, vegetables and whole grains, you’re waking up your Mac, or Ubuntu (after spending four days struggling with the new upgrade) and with the cup of coffee you start a new level of CSS for Whalers. ‘’We’re whalers of the moon, we’re carry our harpoon…”. Being now in a good mood and still having the song in the back of your head, humming and giggling (or the other way around), you are watching the video for level 1, in which Greg Pollack is describing the CSS box model in a funny and interesting way. The short 10-minute video spruced up with nice infographics and fluffy kittens just made its way to your mind. You bought it! The thing is that your mood, or attitude, affects drastically the topic you studying, learning. If the content is dull, it gets even worse. There’ve been many things I was learning / just watching that really attracted me, like O’reilly Head First book series (the most interesting and inspiring technical paper books I’ve ever read!), or Crash Course on Psychology with energetic Hank to name but two.

You game it!

It seems that now every content creator is using gamification to make our learning process as smooth as silk. Gamification, especially badges or award you earn, serves as a real award that you might give to yourself after reaching some (micro) goal, like eating a doughnut after a 10-minute workout. The idea is that, as we can read in the “The Power of Habit’, ‘self-awarding’ makes getting into the habit of something stick. In short you are so attached to doughnuts, that the morning jog is only a side-effect, automatic, without any effort! And the result of eating a doughnut after every workout will make you put it even more effort to burn it!

Traditional is not bad!

As I wrote at the beginning, Google, or any information storage, shouldn’t be our external memory, or the thing you first reach for when having questions to answer. The brain, as any muscle does, has to be trained with different kinds of workouts. That’s why disconnecting from the Internet is so beneficial, as it does not only allow the pieces of information that you keep in your working memory (short-term memory) to go to the long-term memory. Signing up for some offline course in a class setting is not only about socializing, but also about exchanging ideas, and building upon them. Student-teacher relationship is the only way to make your learning process as smooth as possible with helping you to move forward when you’re stuck. This may seem strange to you, but the teachers I have good memories about, are the ones that were demanding some discipline from me, and didn’t tolerate shortcuts. After almost 15 years I can still recall one of the sentences my Polish teacher was saying over and over again: ‘You can forget to eat breakfast. You can forget to breathe, but you can’t forget to do your homework!’ If you’re wondering: eating a good, whole-grain breakfast with vegetables and fruits every day can even increase the chance to do this homework well!

Share what you’ve learn!

It’s said that if you can’t describe something in simple words (or in a down-to-earth way), you don’t understand it. At the beginning of December, I started my first teaching session with my neighbour’s son. Explaining something to a beginner was a kind of challenge – what’s the difference between ‘arrays and hashes’, I asked myself in order to explain it. As hash doesn’t mean anything to most people, a dictionary (another synonym to a hash) was the safer way to explain the concept. To show how it works, I used a real world example – a dictionary (or precisely, Polish-English one). This didn’t only help him to get it right, but helped me too! There are many ways to contribute, to give something back. Thousands of people around the world put enormous effort into creating brilliant open source apps, libraries, or any kind of digital content you might be using, now or in the future. Contributing to something doesn’t only bring some good to this world, but it can be your virtual CV that can attract potential employers.

Last but not least

As you can see in this article, there are many ways to help you learn something more effectively. Before you start complaining about ‘not enough time’, think about how limited access to any knowledge people had 10, or 20 years ago. Start now. What are you waiting for?



Since 2010, we’ve scored hundreds of beautiful goals at Selleo Football. Now we are starting the 5th season with desire for much more.


Healthy Exertion

Let’s be honest, being a developer does not help to stay in good shape much. Apart from control of what we eat, we have to organise some sport activities. Football Selleo was our first sport initiative that is followed by participation in airsoft, running events or volleyball matches.

Team spirit

One of our fundamental rules is to have all Selleo’s developers playing in the same team. Thanks to that, we are improving our teamwork, trust and quick decision taking. Also, it’s great to see how much positive impa



Geeks, Ireneusz Skrobiś

The 3rd edition of Day With Board Games took place on the 13th of September at the new Selleo HQ. As usually, the event was prepared by Bartłomiej Wójtowicz and Tomasz Czana, but this time they also invited their friend Jarek to help during the event as a third board games expert.


What is really interesting, this time we played only three games from previous gatherings: Star Wars: X-Wing Miniatures Game7 Wonders and Letters from Whitechapel. The new games that showed up this time were: Formula DAmong The StarsSurvive: Escape from Atlantis!Rory’s Story CubesLove LetterRobinson Crusoe: Adventure on the Cursed Island and Ooga Booga.


We established two new records. First: the youngest participant: Łucja (daugher of Gabriela and Bartłomiej Danek) is not even half a year old! Of course she did not play, but was really immersed by different boards and game elements  Second record is of course attendance. 18 people spent time together in a friendly but competitive atmosphere. Besides six that I have already mentioned, there were also Arek Janik with his wife Gosia, Grzegorz Rduch with his kids: Oskar and Emilia, Sebastian EwakDawid PoślińskiRadosław JędryszczakMarek Caputa, Adam Dziendziel, my wife Monika and I.


Day with Board Games was once again a great success and everyone wants to take part in it another time. We just have to wait for organizers to establish next date  But while waiting, I encourage you to take a look at timelapse (eight hours in less than two minutes) and photos from the event that is now a history…



Most people think that IT guys, especially developers, live in a house without windows, having no life (being no-lifes). This is not true. At least for Selleo crew.
At Selleo almost everyone practises some sport (jogging, MTB, volleyball, football, basketball, and more – not to mention ASG). Let me focus on the running part of the Selleo.

Before I start, let me pose this question: ‘why do we run?’ It’s simple! Running is not only about endorphins (a lot of happiness). It’s about having the power to solve tasks and figuring out solutions on a daily basis. With full focus. To balance work and life. Period.

As one can read in the bestselling The power of habit’  book, running (or exercising) is a keystone habit that make other areas of life balanced and organized. It requires a lot of discipline and routine like eating healthy food, cutting down on what’s not essential, but results are tremendous.

What really matters is, it doesn’t matter how fast you run, you will always be running faster than couch potatoes.
But let me go back to when it started. Looking from my perspective, it all started about 1 year ago when Tomasz Borowski did his presentation about gamification at event.
He told that there’re apps that will help us to run with love and no effort (OK, just kidding). Many colleagues were astonished with all those progress you can track, these awesome achievements one can win (double-shot, night owl, 3 times in a row, to name a few) using Nike+ mobile app or Endomondo.

From struggle to walk in the part (baby steps, please!)

I want to give you some real achievements my colleagues won. Without them, I wouldn’t write this article (but one about ‘how fast a couch potato can eat crisps’ was still a choice). Tomasz with his 100 starting number on Fiat Race was a great spur to think, ‘hey, I can do that too!’. His first half-marathon was for me like being the ancient runner who died with exhaustion but did the trick! (Tomasz is well if you wonder). Szymon did something magnificent. Like a dark warrior, starting at 11 pm, he ran the distance of a half-marathon. Just did it. My journey was more than ordinary (no unicorns, no heroes). One year ago I did my first one-kilometer run. It was like the 18th battle that changed the world… OK, it actually started a few months before when I started with marches because I thought at the time that I couldn’t did this bloody ONE. Time for unicorns and heroes came pretty quickly! Now a ten-kilometer run is literally like a breeze. Even more! I could run 12.5km finishing at half past one am or doing 15 km on the Sunday in the early morning.

Healthy competition, not a rat race

So far Tomasz, Błażej, Szymon and me took part in the following competitions: Fiat Racecharity run in Tychy City, Żory city race and something special that happened on March, 22.
Błażej and me wanting to celebrate the most happy season of year, Spring, run up Szyndzielnia Mountain (1020m.) doing our first mountain run. For the sake of PR, you should assume that there were no breaks and if you want to hear the true version with all those ‘take it easy, we’re almost there!’, come and visit us. I’m sure that tons of beer (actually a runner shouldn’t do that  or coffee will have to be drunk to hear the whole story (and all those that followed – the season just started!).
I hope that I could encourage some of you to start running. 20 minutes a day is enough to give you real kick-start and lots of energy for the whole day. That time will pass whether you like it or not. Running or exercising will change your life. Remember that what seems like a chore now will one day be just warm-up. This was the case for all of us!
This article wouldn’t be complete if I didn’t give you some useful tips. All of us noticed that running in your neighborhood is like a ripple effect. If you want to impress your neighbor, spouse, boss, or just care about yourself, read on!


Nerdy tips how to run and survive

Early in the morning or late in the evening?

Both are equally good when it comes to empty streets, no people, just you and your breath (unless you want some music). Let me give you two examples why morning is a good choice. If a sunrise doesn’t convince you, seeing and hearing a pheasant coming out from
bushes near you will make you an early bird starting next day. Not to mention roes family crossing your path. It depends where you live, of course, but grizzly would be of similar blessing experience.
Night is good either. Empty streets, low hum, dancing lights and shades under the moonlight… with you feeling that you’re the only one living in the city. Sometimes though, the dose of endorphins won’t allow you to sleep, but the other way around is still a choice – waking up at 3am to run because you can’t sleep.


With or without music?

It depends on so many factors that just follow your gut. But if you really want to enjoy the run (and run is not about struggle, really!), read the above again.


Last but not least

Remember that it’s just the beginning. The best is to come yet! Stay tuned for more!


Geeks, Ireneusz Skrobiś

After the success of the first Day With Board Games that took place on October last year it was only a matter of time before Tomasz Czana and Bartłomiej Wójtowicz will decide to prepare a second edition. We were waiting with anticipation and on the 8th of February it finally happened.

This time was even better than before! There were about 20 titles that we had possibility to choose from (Tomek and Bartek as usually prepared some movies about new games in their collection and posted them online). The titles used this time were: King of TokyoPuerto RicoDominion IntrigueThe Resistance (there were a few games with 10 players participating!), SaboteurStar Wars: X-Wing Miniatures GameGlory to RomeDixitTicket to RideCarcassonne and 7 Wonders.

Second edition was not only bigger because of number of games but also because 17 players participated. Like before it was a really family event. Grzegorz Rduch brought his two kids: Emilia and Oskar. Darek Wylon took his son Tybek. Aga Pawlicka came with her husband Marcin, Bartłomiej Danek arrived with his wife Gabriela, Dawid Pośliński showed up with his girlfriend Agnieszka and Tomek Czana came with Justyna. The whole group was accompanied by Bartek Wójtowicz, Arek JanikSebastian Ewak, and me.

We had a really great time and some of us stayed from 10:00 till 19:00! Boardgaming is a really good way to spend time with competitive but very easy going and fun atmosphere. If you are thinking about it but you are still hesitant to try you can watch how we played in timelapse or on the photos. I think this will encourage you to take a leap and try.


Geeks, Ireneusz Skrobiś

At the 26th of October we had the first edition of Day With Board Games. It was of course prepared by Tomasz Czana and Bartłomiej Wójtowicz. During the preceding days organizers made some tutorial videos about games we were supposed to play and posted them online (you can find them here).

At the day of the event Tomek and Bartek brought 8 titles and prepared 3 tables where the participants could play different games. It was a really family happening this time: Grzegorz Rduch brought his two kids: Oskar and Emilia. I took my wife Monika, Bartłomiej Danek came with his wife Gabriela, and Dawid Pośliński showed up with his girlfriend Agnieszka. The whole group was accompanied by Arek Janik and Sebastian Ewak.

It is easy to count that there were 13 players and I must say that we were the “Lucky Thirteen” because the event was a great success. We tried out a lot of titles: PandemicPower GridDixitCarcassonneLetters from Whitechapel7 Wonders and Ticket to Ride (only Airlines were not used this time). The games were competitive but conducted in a really friendly manner and almost everyone won at least once.

To sum up: all of us had a great time and the Saturday passed by impossibly fast. I think that the next event should take place in about two months and will be at least as fun as this one and gather even more players.


Geeks, Ireneusz Skrobiś

At Selleo, for about a month we have “The Board Games Thursday”. Thanks to two hardcore board game geeks:  and Tomasz Czana, we have the possibility to play awesome games from their collection (20+ titles!). On the photos you can see two titles: “Power Grid” and “Ticket to Ride: Europe“. But we also tried “7 Wonders“, “Dixit”, “Lifeboats” and “Airlines“. Each of these games was pretty exciting so more and more people sign up every week. Tomek and Bartek also have an idea to gather coworkers and their families and play for the whole Saturday. I cross my fingers to make this event happen and of course I will take some photos to share them with you after the game.


Geeks, Ireneusz Skrobiś

Last Friday at Selleo we had mini FIFA’13 tournament. Darek Wylon, Tomek BorowskiBartek Danek and Arek Janik (later substituted for Szymon Kieloch) played many exciting matches. Each player had his moments but there can be only one champion. This time the MVP went to… Darek. The rest of the players already challenged him to play FIFA’14 so let’s get ready to rumble next month.