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_