A pentomino is a shape made of five unit squares joined edge-to-edge. There are 12 of them (named by the letters they resemble: F, I, L, N, P, T, U, V, W, X, Y, Z). A remarkable fact: every one of the 12 pentominoes can tile the whole plane on its own, using only copies of that single shape (rotated or flipped).
Below, each pentomino is shown with one or more essentially different repeating tilings (tilings that are merely rotations, reflections or shears of one another are treated as the same). Some pentominoes admit further tilings — including non-periodic ones — so this is a selection, not an exhaustive list. Each pentomino type has its own colour; the dark outlines separate the individual copies, and the thin grey lines show how each one splits into its five squares.
Outer (pentomino) boundaries use the chosen line width; the inner square divisions use half that width in grey (#888). Every tiling shown was verified to cover the plane with no gaps or overlaps. Fundamental domain size is given as the number of pentominoes that repeat by translation.