Monkey Wrench

About this block

This block is built by starting with a small on-point four-patch center, then adding half-square triangles of increasing size in rounds, using a technique related to Log Cabin piecing, which creates a spiraling, swirl-like effect radiating outward. That on-point center is what sets this apart from Snail's Trail, which uses the same spiral construction but starts from a four-patch set straight rather than on point. Quilt designer Ruby McKim called this design "Monkey Wrench" or "Snail's Trail" interchangeably in the 1920s, though quilters distinguishing between the two by center orientation treat them as related but separate blocks. When four blocks are set together, the spirals interact to form the look of arms swinging around a central point, though getting that illusion right means rotating every other block.