Well, let's start with Pythagoras and the Yang Hui or Pascal Triangle Start=1=point/empty set es with 0 elements el Next row=1,1=edge+its enlargement/set with 1 el: 1 subset ss with 0 el+1full set fs Next row: 1,2,1 a square+2 equal rectangles+a new square/set with 2el=3 ss:1es+2ss with 1el+1fs 1/4