E = (1, -1, 0)
B = (2, 1, 0)
C = (-1, 1, 0)
D = (-2, -1, 0)
poly1, a, b, c, d = Polygon(E, B, C, D)
A = (0, 0, 3)
e, faceABE, faceABC, faceACD, faceADE, arêteAE, arêteAB, arêteAC, arêteAD = Pyramid(poly1, A)
I = Midpoint(arêteAB)
O = (0, 0, 0)
f = Segment(B, D)
g = Segment(C, E)
J = Midpoint(arêteAC)