Black Box Puzzles


I teach testing by giving people things to test. In my workshops, I use real software, and also build small systems to help people have fun with particular techniques. If you want your team to have a great time discovering ways to test, consider my in-house courses.

If in-house workshops don't suit, I run stand-alone public workshops a couple of times a year.

I also do conference workshops and TestLabs – ATD-NL, FiSTB, EuroSTAR and ATD in 2016.

Sign up to my mailing list for workshop/conference discounts, and to be the first to hear about free events and new puzzles. Follow @workroomprds for shorter, more random stuff.


Here is a short selection of tiny applications. I'm not going to tell you what they do. They're puzzles: use your testing skills to discover what you can. If you can describe what they do with a couple of short sentences, that's it.

It's always interesting to share your testing approaches, but you may frustrate others by telling them your solution before they're ready.

... the first 5, from more than a decade ago ...
Puzzle 1
Puzzle 2
Puzzle 3
Puzzle 4 - Altom built a couple of these for real
Puzzle 5 - and a couple of these, too

... mostly one slider, one button, one light ....
Puzzle 6a
Puzzle 7
Puzzle 8
Puzzle 9

... button-based ...
Puzzle 11 (mobile / multitouch / non-flash version puzzle 11)
Puzzle 12
Puzzle 13 (mobile / multitouch / non-flash version puzzle 13)

... newer interface ...
Puzzle 15 (mobile / multitouch / non-flash version puzzle 15)
Puzzle 16
Puzzle 17 (mobile / multitouch / non-flash version puzzle 17)
Puzzle 18

Recently added (only mobile / multitouch / non-flash version )
Puzzle 22

Common elements

These puzzles are generally deterministic, they don't tend to hide what they do, and they typically do simple things. If you think most are random, sneaky or complicated, you should be able to find neater models. The puzzles may well have bugs, but I've not put those bugs in on purpose.

Some have hints, some don't. I'm always open to suggestions for better hints.

The question mark, logo, puzzle name, and camera (if it's there) don't form part of the puzzle, and are broadly similar across puzzles.

They're written in AS3, and run in your browser using flash player. They won't work without the flash player, so phones and tablets are generally out. Local copies may not work well at all. You can probably work out how to decompile them if you want to quiz the code.


Puzzles with a camera logo may send me anonymous information about how you use the buttons and sliders.

Puzzles 15, 16, 17 and 18 will respond to a MIDI Fighter Twister. If you've got one, plug it in. How does having a tactile interface change the way you test?

Can you find Puzzles 10 and 14? Me neither. Maybe later.

If you find a bug, that's super. Log it by emailing me. Some bugs get fixed.

You can use these yourself as much as you like. If you'd like to use these in a commercial setting, drop me a line. I usually say yes and will give you an explicit license. I don't currently intend to open the source code.

The Black Box Puzzles by James Lyndsay are licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Creative Commons License


James Lyndsay, Workroom Productions

@workroomprds, +447904158752

I'm a test strategist with years of broad experience and an interest in adaptive approaches. If you want advice, or if you want me to work with you, I'd be delighted to have a chat. Get in touch.