Simple Sierpinski triangle using ruby2d.

sierpinski.rb

require 'ruby2d'

set title: "Sierpinski Triangle", background: "white"

vertices = [[Window.width / 2, 50, "blue"], [Window.width / 2 - 150, 350, "green"], [Window.width / 2 + 150, 350, "red"]]
point = [250, 200]

update do
  v = vertices.sample
  point = [0.5 * (point[0] + v[0]), 0.5 * (point[1] + v[1])]

  Triangle.new(
    x1: point[0], y1: point[1] - 3,
    x2: point[0] - 3, y2: point[1] + 3,
    x3: point[0] + 3, y3: point[1] + 3,
    color: v[2]
  )
end
show