<script src="https://cdn.jsdelivr.net/npm/p5@1.4.1/lib/p5.min.js"></script>
<!-- p5.js より後に追加する -->
<!--
<script src="https://cdn.jsdelivr.net/npm/p5.capture@1.1.0/dist/p5.capture.umd.min.js"></script>
-->

html, body {
  margin: 0;
  padding: 0;
}
canvas {
  display: block;
}

f=0
draw=_=>{
  f++||
    createCanvas(W=300,W)+
    stroke(255)+
    strokeWeight(4)
  translate(W/2,W/2)
  background(0,10)
  R=W/3
  point(R*cos(t=f/TWO_PI),R*sin(t))
}