>>> from Vec3D import Vec3D
>>> u = Vec3D(1, 0, 0)  # (1,0,0) vector
>>> v = Vec3D(0, 1, 0)
>>> print u**v # cross product
(0, 0, 1)
>>> len(u)     # Eucledian norm
1.0
>>> u[1]       # subscripting
0
>>> v[2]=2.5   # subscripting w/assignment
>>> u+v        # vector addition
(1, 1, 2.5)
>>> u-v        # vector subtraction
(1, -1, -2.5)
>>> u*v        # inner (scalar, dot) product
0
>>> str(u)     # pretty print
'(1, 0, 0)'
>>> repr(u)    # u = eval(repr(u))
'Vec3D(1, 0, 0)'