Stephen Hayes recently contacted me about his puzzle app Atoms HD. The objective is to recreate various chemical molecules by sliding pieces in the grid.
Look at image 1: excellent, fun drawing of the typical chemist - balding, white coat, glasses, old, eccentric.
Look at image 2: in the bottom left corner is the methane molecule. You actually have 2 tasks. The first is to figure out where in the grid you can fit the molecule. The second is to slide the atoms - 1 at a time - until the molecule is formed. Note: the atoms will slide all the way until they hit an obstacle.
Atoms HD is definitely a cool puzzle app for young chemistry students.