<canvas width = "400" height = "400"></canvas>
<h1>Meu Esquadro!</h1>
<script>
var tela = document.querySelector("canvas");
var pincel = tela.getContext("2d");
pincel.fillStyle = "yellow"
pincel.fillRect(0, 0, 400, 400);
//linha 1
pincel.fillStyle = "black";
pincel.beginPath();
pincel.moveTo(50, 50);
pincel.lineTo(50, 400);
pincel.lineTo(400, 400);
pincel.fill();
//linha 2
pincel.fillStyle = "white";
pincel.beginPath();
pincel.moveTo(100, 175);
pincel.lineTo(100, 350);
pincel.lineTo(275, 350);
pincel.fill();
</script>
