I’ve had several people ask me for more detailed information on how to construct the heel.

A good idea might be to trace the diagram in the book, cut it out, and tape it together to get a sense of the 3-D form the heel takes.

The heel is a smooth hexagon. I cast on stitches for two sides of the heel hexagon, then pick up stitches for the other four sides from two hexagons that are side by side. This causes the heel to form the cup shape you need. Also, at the sides of the heel (the ankle) there will be four hexagons joining together, which hexagons do not naturally do.