so i know that there are different shapes of faces oval,round,square,etc............. so i want to draw my own skull and for instance if some one is a square headed, can skull's width= height (i mean the measurement could it vary so far) , and when i look in different skull's reference each of them vary in the shape of details as: the eye socket and zygomatic bone...etc........so it's really annoying for me and i started to learn from some books but most of them don't approach this area, they assume a certain shape of the skull and study it.....so my question here... the parts and the proportions that could vary to make different people shapes and to be anatomically right....i don't know my question is clear or not but hope to help me plz .......thnx in advance