Quadphos is a grid-based rule deduction logic puzzle game. Each puzzle consists of a grid and several numerical clues. Your goal is to light up the cells to satisfy all the numerical clues. The symbols next to the numbers represent the specific rules that these clues follow. For example, a number might indicate the number of lit cells within its range. The game doesn't directly tell you these rules. You'll need to deduce and verify their meanings through a series of levels. As you solve puzzles, you'll continually refine your guesses, or even discard them entirely, until you discover a more exciting perspective.