p5 Pillow drawing

pillow_p5.js

const s = (p) => {
    const w = 400;
    const h = 400;
    
    // Center coordinates
    const x0 = 200;
    const y0 = 200;

    // Radius
    const r = 150;

    var angle = 0;

    p.setup = () => {
        p.createCanvas(w, h);
        p.stroke(0, 0, 0, 10);
        p.background(225);
    };

    p.draw = () => {
        
        var a, b = 0;
        var numPoints = 10;

        for(var i = 0; i <= numPoints; i++) {    
            // Pillow
            var x = x0 + r * Math.cos(2 * Math.PI * i / numPoints - angle);
            var y = y0 + r * Math.sin(2 * Math.PI * i / numPoints + angle);   

            if (i != 0) p.line(a, b, x, y);
            a = x;
            b = y;
        }
        angle += 1;
    };
};

let myp5 = new p5(s);