<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.beginPath();
pincel.fillStyle = "yellow";
pincel.strokeStyle = "yellow";
pincel.moveTo(300, 50);
pincel.lineTo(50,200);
pincel.lineTo(550,200);
pincel.fill();
pincel.stroke();
pincel.beginPath();
pincel.fillStyle = "yellow";
pincel.strokeStyle = "yellow";
pincel.moveTo(300,350);
pincel.lineTo(50,200);
pincel.lineTo(550, 200);
pincel.fill();
pincel.stroke();
pincel.beginPath();
pincel.fillStyle = "darkblue";
pincel.arc(300, 200, 100, 0, 2*3.14);
pincel.fill();
</script>
