ring = [[0,0],[-90,0],[-180,0],[90,0],[0,0]]
area = 6.283185307179588
ring = [[0,0],[90,0],[-180,0],[-90,0],[0,0]]
area = 6.2831853071795845
ring = [[0,0],[-90,0],[-180,0],[90,0],[0,0]]
area = 0
ring = [[0,0],[90,0],[-180,0],[-90,0],[0,0]]
area = 0