ShapeGapFill shows a simple board with one missing piece shaped as a circle, square, or triangle. Three options appear below, and only one matches the gap. Choose correctly for three points. Wrong picks count as mistakes, and three mistakes end the run. Rounds refresh endlessly, and later boards look more alike to raise the challenge. Compare hole outlines carefully, ignore similar colors, and commit once you see a clear match. Steady recognition under rising similarity decides how far each endless gap-fill run goes.