This is a ball set to move at a constant speed in a butterfly pattern

Think that's easy? Try it yourself perhaps?

The butterfly curve is a parametric equation:

x = cos(t) * (exp(cos(t)) - 2*cos(4t) - (sin(t/12))^5)
y = sin(t) * (exp(cos(t)) - 2*cos(4t) - (sin(t/12))^5)
    

Check this link for more on the curve: https://en.wikipedia.org/wiki/Butterfly_curve_(transcendental)