Catoptrics concerns the properties of optical systems containing mirrors, where beams of light bounce like the lines of eyelets in this asymmetric triangle shawl.

The pattern includes both written instructions and a chart for Rows 9-117 of the shawl; later rows have only written instructions. As much as I prefer to use charts, this one simply gets too big to be useful.

This shawl uses almost all of the yarn called for, so if your gauge is any looser than recommended you may need another skein.