I managed to get IQ mission via apps gone free and think it's one worth blogging about. It is tricky and really requires you to use those computational thinking skills. At the time of writing it has 66% off in the app store.
You visit different places, where there are a number of levels each with a variation of the same problem.
So this was the first place I visited (Rapa Nui) and it became tricky very quickly - level 4 made me think and I got it wrong a few times. You have to place your masks in their respective coloured holes, but your masks can only move horizontally or vertically, and will keep going until they hit something. That's the part that makes it tricky. You really have to be strategic.
I have also visited the London section, which requires you to complete the laser beam without going over yourself. We've all seen problems similar to this before and it's great to do it on the iPad, rather than wasting all those pieces of paper ...
There are 6 more places and puzzles to visit, but I am not allowing myself to do so until I've got a little bit further on these. Perseverance- I'm trying to practice what I preach!