If you repeatedly apply one of three simple functions picked at random you might end up with Sierpinski triangle.
https://en.m.wikipedia.org/wiki/Sierpi%C5%84ski_triangle
It basically using the fact that fractal is self similar. So picking one function (that scales whole triangle to one of the one thirds) and transforming single point on a fractal into a new point also gets you a point on the fractal.
If you repeat this process many times you get a lot of points of the fractal.
You can even start the process at any point and it will "get attracted" to the fractal.
That's why fractals are called strange attractors.