High Tide

About High Tide, from BoardGameGeek:

Waves come in, sweeping up the ocean floor. High Tide is a strategic stacking game for two players inspired by mutualistic relationships found in the natural world. The game is played without a board on any flat surface with 19 wooden hexagon tiles: 7 tiles for each player and 5 neutral tiles. The tiles are randomized in a grid at the start of each round, leading to over six million different starting positions - and millions more unique and pretty end states! Players take turns moving one tile of their own color or a neutral color. The twist: A tile must stack onto another tile so that it is higher up than it was before. You want to cover your opponent's tiles and have the most uncovered tiles by the end of the round. When a player cannot take a legal move, the round ends. The first player to win three rounds wins the game. -description from the designer