<canvas

  width="400"

  height="400"

  canvas_background="220"

  angle_mode="DEGREES"

  circle_angle="0"

>

  <square

    anchor="200, 200"

    fill_color="'red'"

    angle="circle_angle"

    circle_angle="circle_angle + 1"

  ></square>

  <circle anchor="100, 100"></circle>

</canvas>

​