What's a good Android game to keep my brain from turning to mush while I'm waiting for the school bus, something that doesn't need internet?

So, I was looking for something to keep me occupied while waiting for the school bus in the mornings, you know, something other than just staring at my phone. My students actually showed me this game, Word Hike. It's one of those word puzzle things, but it's got a bit of a twist. It's surprisingly intuitive, took me a few days to figure out all the features, but even I could get the hang of it. What's really great is that it works offline. Out here in Ohio, cell service can be spotty, especially in the more rural areas where some of my students live. So, not needing internet is a big plus. It's like having a teaching assistant in your pocket, but instead of grading papers, it's keeping your mind sharp with word puzzles. Once you get the hang of it, it's quite enjoyable. I'd recommend it.