I believe it was a Spoonflower contest that spurred me to redo a tessellation I had done by hand in the 90s. I had accomplished this one in symmetry group Cmm, built within a 30-60-90 degree triangle, with mirrors on two sides and a two-way rotation point on the hypotenuse.

A pen and ink drawing with coloured pencil shading. And the revised version drawn on my iPad.

Cheers,

Francine