A: (3, 0, 0)
u: (-1, 0, 1)
v: (0, 1, -2)
w: (0, 0, -1)
B: A + u
C: B + u
D: C + u
a = Vector(A, B)
b = Vector(B, C)
c = Vector(C, D)
E: D + v
F: E + w
d = Vector(D, E)
e = Vector(E, F)