Lissajous curves

All the standard trigonometric functions such as sin, cos, tan, and so on are represented by universal functions in NumPy (see https://www.khanacademy.org/math/trigonometry). Lissajous curves are a fun way of using trigonometry. I remember producing Lissajous figures on an oscilloscope in the physics lab. Two parametric equations describe the figures:

x = A sin(at + π/2)
y = B sin(bt)