(let [canvas (js/document.getElementById "canvas-1")
      ctx (.getContext canvas "2d")
      width (.-width canvas)
      height (.-height canvas)]
  (set! (.-fillStyle  ctx) "red")
  (.clearRect ctx 0 0 width height)
  (.fillRect ctx 0 0 width height)
  (set! (.-fillStyle ctx) "blue")
  (.fillRect ctx 100 100 50 50)
)