The generation is quite slow so make sure to turn on turbo mode by doing (shift + green flag) and it will happen almost instantaneously.
The Seirpinski Triangle is a fractal composed of triangles that progressively decrease in size. The fractal is generated by finding the midpoint of a random vertice of the triangle and a point within the triangle. The process is repeated with the midpoint being used as the new point within the triangle many times until the fractal is formed.