window.onload = setup2d;

        function setup2d() {
            const canvas = document.getElementById("my-canvas");
            const context = canvas.getContext("2d");
            context.fillStyle = "rgb(200,0,0)";
            context.fillRect(10,10,100,100);
            context.fillStyle = "rgb(0,200,0)";
            context.fillRect(20,20,100,100);
            context.fillStyle = "rgb(0,0,200)";
            context.fillRect(30,30,100,100);