Sat in Kwik-Fit yesterday for an “about an hour” MOT that took two and a half, I had a rummage through a bunch of games I stuck on my tablet a while back, and stumbled over a bit of a gem which I’d like to recommend (if you like that sort of thing).
Euclidia isn’t in fact something you’d catch from a late night tryst but rather a geometry game where you’ve to draw various geometric things using a (virtual) straightedge and pair of compasses. It’s basically Technical Drawing Lite. In its criticism it’s not very heavy on clues / geometry tutorials, but it was a nice gentle no-BS game that passed a little time.
When I ran out of GSCE maths and came unstuck, I looked at “also by the publisher” and they do a similar game based loosely on Pythagoras which I think is actually more accessible.
https://play.google.com/store/apps/details?id=com.hil_hk.pythagorea&hl=en_GB
https://itunes.apple.com/us/app/pythagorea-geometry-on-square-grid/id994864779
There’s also Pythagorea 60° which I’m assuming is a follow-up, I’ve not looked at it yet.