Brain Jam

Brain Jam is the classic gridlocked car park puzzle with an unusual meter attached. Its opening page claims thinking burns real calories, so every jam you clear counts as a tiny workout, and the counter in the corner keeps track of it.

The board is a six-by-six car park filled with pixel cars, tankers, ambulances and vans. One car is red, the gap in the right-hand wall is marked with a yellow barrier, and getting that car through it is the whole job.

The rules page is specific about the meter. The counter runs while you think, not while you drag. Wait longer without moving and it speeds up to three times. Finishing in par moves pays one and a half, while a hint cuts it to six tenths.

All of that is visible on the board. Sitting still pushed the multiplier from two to three, and the first car that actually moved dropped it straight back to one and four. Level one is rated at six moves, with undo, restart, hint and a daily puzzle below.