(def canvas (js/document.getElementById "canvas-1"))
(def ctx (.getContext canvas "2d"))
(def width (.-width canvas))
(def height (.-height canvas))
(def colors ["red" "blue" "green" "yellow" "magenta" "purple" "pink"])

(set! (.-fillStyle  ctx) "gray")
(.clearRect ctx 0 0 width height)
(.fillRect ctx 0 0 width height)
(set! (.-fillStyle ctx) (rand-nth colors))
(.fillRect ctx 100 100 50 50)