createCanvas(400, 400);

}

​

let cOffset = 0;

function draw() {

    const inc = height/100;

    colorMode(HSB);

    for(let y = 0; y < height; y += inc) {

        let h = (y / height) * 360;

        fill(abs(h+cOffset)%360, 100, 100);

        noStroke();

        rect(0, y-inc, width, y);

    }

    cOffset -= 5;

}