let a=0;
let x=0;
let y=0;
let r=100;
function setup(){
createCanvas(800,800);
noStroke(0)
colorMode(HSB,360,100,100,1)
}
function draw(){
background(200,0);
fill(random(255),50,100,1)
a++;
x=r*cos(radians(a))+300;
y=r*sin(radians(a))+300;
rect(x,y,10);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.1.9/p5.min.js"></script>