Plot the following parametric curves. Describe in words how the point moves around the curve in each case.
a. x = cos(t2 - t), y = sin(t2 - t)
b. x = cos(2t2 + 3t + 1), y = sin(2t2 + 3t + 1)
c. x = cos(-2 In t), y = sin(-2 In t)
d. x = cos(sin t), y = sin(sin t)