What's a good iOS game for when I need something engaging but not overly taxing, perhaps during a long flight or while waiting for research data to process?

I find Grand Hotel Mania to be an interesting implementation of classic time-management gameplay. The core mechanic involves efficiently managing hotel resources and guest requests. What I appreciate is the game's progressive difficulty curve; it keeps you engaged without feeling overwhelmed, which is ideal when I need a mental break from academic work. The visual design, while not groundbreaking, is clean and functional, and the cross-platform compatibility is a definite plus. I can easily pick up where I left off on my iPad after playing on my iPhone. While it might not directly contribute to my research, I consider it a well-researched design for stress relief.