The book is designed to open flat while being used, and the texts
point out important details to be observed. The heads of waterfowl
drafted in intricate detail. Exact specifications regarding head
thickness, eye color and size, and the fine points of the bill from
top, bottom, and profile views. Four patterns are included for each
bird: full-sized, 1/2, 2/3 and 1/4 of the actual size.