The Propeller quilt block forms pinwheel designs when the blocks are set side by side, as evidenced in the quilt layout on the left illustrated below.

These pinwheel designs are even more evident in the quilt layout on the right, when setting the blocks on point and using the dark background fabric as the setting triangles along the edges of the quilt. This technique makes those features pop. The central motif of blank blocks in an alternate colour adds an extra design element to the quilt.