Hoop is played on a hexhex board of size 4-6. Each player has a pool of stones in their own color in addition to a pool of shared neutral stones.
Rules:
Each turn, you first place a neutral stone on an empty cell or replace one of your stones with a neutral stone. Then, you place a stone of your color on an empty cell.
If there are no empty cells, so you cannot place a stone of your color, you may still replace one of your stones with a neutral stone.
Balancing mechanism: On the very first turn, the first player only claims a cell, but does not place a stone.
The game is over as soon as one player completes a loop of neutral stones. The cells inside the loop can have any combination of stones and empty cells – it doesn't matter.
—description from the designer