Following the theme of what shapes can fit in a 2 x 2 square (see #11, #12, #15, #16, #18, #20…), I’ve been playing around with half-rectangle triangles again. I tried to prevent adjacent shapes from joining on their horizontal or vertical lines, but a few overlaps snuck in (e.g. fifth row down, about two thirds of the way across… a shaded and an unshaded triangle have their backs together).

I tried to avoid the heaviness of those adjoining shapes by shading in the back/forth triangles while leaving the up/down triangles empty (the design could also be rotated 90 degrees to alternate that colour scheme).

This quilt design could be made from rectangles and half-rectangle triangles, or by adding a triangle to a square. The latter method would waste fabric (the other half of the half-rectangle triangle that’s cut away from the square); the former would involve a bit more sewing and more seams. I’d prefer the former just for the sake of precision – I know there’s no way I’d manage to get that triangle in the square just right.