Branches and Twigs and Thorns, also known as Barsoomian Go, is Andrew Plotkin's game of pyramids branching across a chessboard, in which a player gains points when opponents point at their pyramids, and loses them when their own pyramids point at their opponents'.

• Rules
• BTT at BoardGameGeek
• BTT at the Looney Pyramids wiki
• More Pyramid Games at this wiki

In addition to the final version of the game, two variants are available:

• Arcade is the same game scaled down to 9 pyramids per player (from 15) for Pyramid Arcade and a quicker game. (This variant was suggested by Avri in the BGG forums.)
• Martian Go was the original version of the game. It used slightly different rules for setup (large central roots with no null squares) and scoring (penalties only), and led to a lot of tied games.

A game of pyramids branching across a chessboard, in which you gain points when opponents point at your pyramids, and lose them when you point at theirs.

Inventor: Andrew Plotkin

See Andrew Plotkin: Barsoom / BTT.

When the board holds players × 16 pyramids, or a player has no legal placement, highest score wins. Tied high scores share the win.

You gain points when an opponent's pyramid points at yours, and lose points when yours points at theirs.

Rectangular board sized for the player count. 2–6 players. Default Icehouse stash of 15 pyramids per player (small, medium, large) with pointing (no uprights).

Place a pyramid on an empty cell, pointing at the root or another pyramid. Scores are updated for both players involved whenever one player's pyramid is placed pointing at a pyramid owned by another player.

9 pyramids per player (Pyramid Arcade version).

Original setup (large central roots, no null squares) and penalty-only scoring. With more than 4 players, setup uses the standard layout but scoring is as for Martian Go.

• Current engine version: 20260308 (2026-03-08). On Abstract Play since 2026-03-19.

• 3, 5, or 6 players use a normal rectangle rather than a Martian chessboard.

• https://boardgamegeek.com/boardgame/17298/branches-and-twigs-and-thorns
• https://www.eblong.com/zarf/barsoom-go.html