A = {(1,2), (2,3), (3,4), (4,5)}
B = {(5,10), (10,5), (50,25), (25,50)}
C = {(-5,5), (5,15), (15,-15), (-5,-5)}
D = {(2,-1), (-1,-1), (-2,1), (1,-2)}
E = {(-2,1), (1,-1), (-2,1), (1,-2)}
F = {(0.5,1), (1,-1.5), (-0.5,1), (-1,-2) SHARP
