If you look closely at Sunday sketch #81, you can see that the inside halves of each arrow create a closed octagon in the centre of each block. I decided to take that part of the block  (which kinda looks like a circular saw blade) and tile it on its own.

Of course, that tiling brings up some really interesting secondary shapes: octagons, zig-saggy diamonds, and some wonky 8-pointed stars. It can be easier to see them if I redo the sketch with reverse shading.

I think when I sketch by hand that I pay more attention to the shapes, and see more possibilities for alternative designs and colours than I would when I use Excel or Illustrator. Instead of just creating one block and cutting-and-pasting it to get repeats, I’m re-drawing it again and again, which gives me time to think about each line and how I might manipulate it to get something new.

This design could be made into a quilt pattern using half-square triangles and squares.