Primrose is a game that presents a deep puzzle that is completely fresh. Primrose's gameplay is deceptively simple: Surround tiles of one color with another color to clear them. The surrounding tiles flip color, leading to possible chain reactions. Larger groups cleared and longer chain reactions are awarded more points. This simple setup has many interesting emergent properties, creating a challenging game without resorting to external gimmicks like time pressure. The game also features a world-wide online high score board complete with instant replay, move-by-move, of all top-scoring games.