def get_torque():
    """Use sympy to perform some simple math.
        R x F
        C_m x F
        w x r
    """
    import sympy as S
    x, y, z, fx, fy, fz = S.symbols('x, y, z, fx, fy, fz')
    R = S.Matrix([x, y, z])
    F = S.Matrix([fx, fy, fz])
    print('Torque:', R.cross(F))
    cx, cy, cz = S.symbols('cx, cy, cz')
    d = S.Matrix([cx, cy, cz])
    print('c_m x f = ', d.cross(F))
    wx, wy, wz = S.symbols('wx, wy, wz')
    rx, ry, rz = S.symbols('rx, ry, rz')
    w = S.Matrix([wx, wy, wz])
    r = S.Matrix([rx, ry, rz])
    print('w x r = %s' % w.cross(r))
