let draw =
  () {
    case Dom.Canvas.fromDomElement(canvas) {
      Maybe::Just(el) =>
        {
          el
          |> Canvas.ellipse(100, 100, 50, 75, 3.14 * 2, 0, 0)
          |> Canvas.fill
          el
          |> Canvas.beginPath
          |> Canvas.ellipse(100, 100, 50, 75, `Math.PI` / 4, 0, 2 * `Math.PI`)
          |> Canvas.stroke
          // Draw the ellipse's line of reflection
          el
          |> Canvas.beginPath
          |> Canvas.setLineDash([5, 5])
          |> Canvas.moveTo(0, 200)
          |> Canvas.lineTo(200, 0)
          |> Canvas.stroke
          ""
        }
      Maybe::Nothing =>
        ""
    }
  }
{
  await Timer.timeout(0)
  draw()
}
<canvas as canvas
  width="200"
  height="200"/>