From the description: This is my family’s favourite sock because it is so easily customised to fit any foot. And it’s a Sister sock because my sister and I use it to make matching socks. We live continents away from each other, but that doesn’t stop us. A basic design with a simple afterthought or peasant heel it is also a sock knitter’s blank canvas, making cable, lace or textured pattern socks easy to create. The Sister Sock will maximise the look of your favourite self-patterning yarn - look, Mum, no colour-pooling - and lets you use any leftover bits to replace a worn-out heel.When the time comes, just unpick the old and knit it anew. Clever and thrifty, this one.