What's a decent iOS game that'll keep my mind busy during lunch breaks without a bunch of BS?

Look, I need something to kill time on my lunch break that doesn't require a whole lotta thinkin'. Coloring Match fits the bill. It's all about matching colors, which sounds simple, and it is, but it's kinda addicting. It's not built like a brick house or anything, but it hasn't crashed on me yet, even after dropping my phone a couple of times. The only real problem is the ads. They pop up more than I'd like, but hey, it's free. Just gotta deal with it, I guess. Keeps my mind off the job for a bit, and that's what matters. Battery life seems alright, hasn't drained it too bad yet. Gets the job done for what I need.