My latest obsession is sashiko, a Japanese form of embroidery with beautiful repeating geometric patterns. It’s a folk art that evolved to strengthen cloth, extend its lifespan, and repair torn clothes. Rather uniquely it’s also intended to be stitched with the fabric in your hands rather than in a hoop.
One thing I really love about it from a technical sewing standpoint is that traditionally you don’t use knots at all, but it’s still a strong stitch. Quilters do something similar with what’s called a waste knot that gets snipped away, but this skips the knot step entirely.
There are specific paths you follow while stitching these patterns so that you don’t waste thread. They vary in complexity from simple lines, triangles, and curves, all the way up to tiny repeating patterns that practically replace the cloth with thread.
I don’t have nearly enough patience to do the complex ones like that, but the more simple stitches are so relaxing.