I’ve been using
pin-up-live.in specifically for pre-study warmups. The logic and reflex games take just a minute or two to complete but really help wake up your mind. They’re not childish — they’re clean and minimalistic — yet they don’t overwhelm you either. I appreciate that the games start immediately, without tutorials or forced intros. It helps me focus without wasting time. Sometimes I do two or three puzzles and then jump straight into my study plan. For mental priming, it’s extremely effective.