This is one of the oldest and most enduring designs in American patchwork: four half-square triangles arranged so the darker fabric spins around a central point, evoking the blades of a windmill. It belongs to the Four-Patch family and traces back to the early 1800s, with some sources placing its earliest use in decorative quilts as far back as the late 1700s. The design likely drew on the real, everyday sight of water-pump windmills that powered wells and mills across farms and small towns, a functional piece of pioneer life that quilters translated into fabric. Beyond standing on its own, the Pinwheel frequently shows up as a component inside larger, more complex blocks, including the center of Sawtooth Star.