My TILs of the week 9/20

Mob programming

This week my team did a lot of mob programming. Our setup looked like this:

  • 4 developers
  • One of them is typing
  • The other 3 give the instructions
  • We rotate every 10 minutes

The results were great. We managed to make great progress on a complicated technical issue and at the same time managed to share knowledge on a legacy code base. It was also a great way of showinig our development setup, tools and shortcuts we are using. This way of workinig certainly improved the spirit within the team.

Product risk vs. consumer risk

This concept was mentioned in The mom test book which I am currently reading.

Image fromĀ FCIT

Customer interviews are great If you are not sure whether you have consumers for your product. Your customer risk is high. Sometimes though the product carries more risk.

The example given in the book was about a “bar crawl” app. Bar owners are happy to give discounts if you fill their place because they would make a lot of money. Customers would definitely use an app that always takes them to buzzing places with cheap drinks. There is little risk you won’t find customers for such an app.

In this example however, all the risk is in the product. Will you actually be able to deliver a product and gain a critical mass? If you have product risk you might come to false conclusions only validating the customer. To tackle product risk you have to release early and iterate. Bring your product in front of the customer as quickly as you can!

En Passant

I started playing chess a few months ago. However, only now did I encounter the En passant move. At first I thought I had discovered a bug in a widely used chess app.

The explanation for it is actually quite reasonable and shows how old chess is:

The en passant capture rule was added in the 15th century when the rule that gave pawns an initial double-step move was introduced. It prevents a pawn from using the two-square advance to pass an adjacent enemy pawn without the risk of being captured.

This was a nice reminder of the concept of Unknown Unknowns.

COUNTIF in Google sheets

This is probably a basic function for all Excel wizards out there. Since I usually solve such problems in code and not in an Excel sheet it was still a nice lesson to learn. I used the COUNTIF function to calculate some simple statistics to analyse which topic is under- or overrepresented in our story preparations.