H by HexaPhoenix, the first in the "Periodic Table" series, is a game where you have to ensure the creatures either Hilimi or Halama can complete a full rotation on their circle without colliding with anyone else. The game has 20 levels.

Gameplay

The game opens with a creature affixed to a circle. There are multiple circles per level, and they overlap at different points. The creatures remain in a fixed position until you tap the creature. This causes them to move. You complete a level successfully if you're able to make every creature make a full rotation once without colliding once with any neighbour.

Levels 1-10 feature only blue circles and green creatures, they rotate clockwise. Levels 11-20 introduce red circles with yellow creatures, those move anti-clockwise. (It is unspecified which of these are Hilimi and Halama.)