Nine Squares, One Hole
Each step divides every remaining square into a grid of three by three and removes the middle one. The pieces shrink to a third of their width each time, which is why the carpet stops at step 3 on a printed page.
A Grid of Holes to Color
At step 3, the 73 holes range from one large square in the center to 64 tiny ones. Coloring them by size, or by step on the dedicated page, shows how the pattern nests inside itself.
Described in 1916
Wacław Sierpiński presented the carpet in 1916, a year after his triangle. It keeps eight ninths of its area at each step, yet after many steps almost nothing of the square is left.