Spire

On your turn, either place a ball of your colour, or place a neutral ball and then a ball of your colour. No 2×2 of balls may include more than two of the same colour, and you cannot place a colour on a platform that already holds two balls of that colour. The first player who cannot move loses.

Inventor: Dieter Stein

See BoardGameGeek: Spire. Played on a Shibumi pyramid.

5×5 Shibumi (size-5).

• Current engine version: 20240602 (2024-06-02). On Abstract Play since 2024-06-08.

• One click places your colour; two clicks place neutral then yours. If the first cell allows only one of those, it commits automatically.

• https://boardgamegeek.com/boardgame/113641/spire