I've spoke about Noodles before. It's a fun relaxing puzzle game on iPad that I think is worth checking out. The developer Lummox Labs has posted some interesting blog posts that detail some of the mathematics behind Noodles, as well as the code. Really useful for other developers out there that want to learn.
I'll start off with this link. That is pretty much amazing, and I wish I had known about it when I started building the hex games. The trickiest things with hexagons (ignoring design challenges) is the math in placing them because columns are offset, and the hexes don't have equal height and width. Read up there on how to do that math. Or do high school trig again. Okay, so what is a Noodles puzzle, as a data structure? Well, if you think of the pieces as nodes and the connections between them as edges, it's a graph. Let's say an edge exists between two nodes (x, y) and (a, b) only if they both connect to each other.
It's a great read for anyone interested in game design. Make sure to check out the full post here.