function setup() {
createCanvas(600,600);
background(300);
}
function draw() {
for(let x=50;x<600;x+=70){
for (let y=50;y<580;y+=70){
fill(550,50,550,50)
ellipse(x,y,70,70)
}
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.1.9/p5.min.js"></script>