Treeblox is an abstract strategy board game in which two trees compete for sunlight in three-dimensional space. The game starts with an empty board. Players then take turns placing cubes that represent leaves and branches. Unshaded leaves — that is, leaves that are visible when the board is viewed from above — count as active and supply their tree with energy to grow further. Your goal is to shade your opponent's leaves while keeping your own leaves open to the sun. Each player starts with one leaf in a space on the 4x4 game board. On a turn, if you have 1-2 unshaded leaves, you place one piece on the board, whether a branch or a leaf; if you have three or more unshaded leaves, then you place up to two pieces. You can place nothing in a leaf, so a leaf serves as an endpoint for growth. If you place a branch, however, then you can add a branch or a leaf to any available side of that branch. You can have multiple branches growing on the game board, and the branches and leaves can extend outside of the 4x4 game board. If you build high enough, you can shade an opponent's leaves. When a player has placed their final piece, whether because they've placed everything or they have no legal placements available, the other player goes through a "final growth" phase in which they place everything they can. At that point, whoever has the most unshaded leaves wins. If you ever have zero unshaded leaves during play, you lose immediately.