"As with the hand, you should not hesitate to take off your shoes and use your own feet as references, when the setting allows it!
The bones of the foot are arranged to form 3 arches that give it the strength to support our bodies. The first two shape the bottom of the foot and the third the upper part. Squeeze the sides of your foot and note how rigid they are: the bottom of the foot is not soft and does not deform under pressure. This means that no matter the position of the foot, the indentations of the arches will always show in an adult foot."