Source code for a drawing which is an attempt at reconstructing this image: http://geometrydaily.tumblr.com/image/52626315896

trap-clone.clj

(ns trap-clone
  (:use quil.core))

(def screen-w 1920)
(def screen-h 1080)

(defn setup []
  (smooth)
  (no-stroke)
  (no-loop)
  )

(defn general-triangle [vs c]
  (apply fill c)
  (begin-shape :triangles)
  (doseq [v vs]
    (apply vertex v))
  (end-shape)
  )

(defn backward-triangle [w c]
  (general-triangle [[0 0] [(* 0.866 w) (* 0.5 w)] [0 w]] c)
  )

(defn forward-triangle [w c]
  (general-triangle [[(* 0.634 w) 0] [(* -0.25 w) (* 0.5 w)] [(* 0.634 w) w]] c)
  )

(defn draw []
  ; AAARRRGGGHHH. Need to figure out how to actually compute rows and columns
  (let [triangle-width 50
        triangle-height (* 0.866 triangle-width)
        rows 38
        columns 21
        bg-color 255
        tri-color1 [10 50 10]
        tri-color2 [10 10 50]]
    (background bg-color)
    (translate triangle-width triangle-width)
    (doseq [y (range rows)]
      (push-matrix)
      ; Stagger rows
      (if (even? y)
        (translate triangle-height 0))
      (doseq [x (range columns)]
        ; Randomly alternate triangles 
        (let [coin-toss (rand-int 2)]
          (if (zero? coin-toss)
            (backward-triangle triangle-width tri-color1)
            (forward-triangle triangle-width tri-color2)))
        (translate (* 2 triangle-height) 0)
        )
      (pop-matrix)
      (translate 0 (* 0.5 triangle-width))
      )
    )
  (save "trap-clone.png")
  )

(defsketch main
  :title "trap-clone"
  :setup setup
  :draw draw
  :size [screen-w screen-h]
  :renderer :opengl
  )