<canvas width="600" height="400"></canvas>
<script>
var tela = document.querySelector("canvas");
var pincel = tela.getContext("2d");
pincel.fillStyle ="green";
pincel.fillRect( 0, 0, 600, 400);
pincel.fillStyle = "yellow";
pincel.beginPath();
pincel.moveTo(50, 200);
pincel.lineTo(300, 30);
pincel.lineTo(550,200);
pincel.fill();
pincel.beginPath();
pincel.moveTo(50, 200);
pincel.lineTo(300, 380);
pincel.lineTo(550,200);
pincel.fill();
pincel.fillStyle ="darkblue"
pincel.beginPath();
pincel.arc(300, 200, 100, 0,2 * 3.14);
pincel.fill();
</script>
