<canvas width="600" height="400"></canvas>
<script>
var circulo = document.querySelector('canvas');
var five = circulo.getContext('2d');
five.fillStyle = 'lightgray';
five.fillRect(0, 0, 500, 400);
function desenhaCirculo(x, y, raio, cor) {
five.fillStyle = cor;
five.beginPath();
five.arc(x, y, raio, 0, 2*3.14);
five.fill();
}
desenhaCirculo (250,200,20,'red');
desenhaCirculo (210,200,20,'orange');
desenhaCirculo (290,200,20,'black');
desenhaCirculo (250,240,20,'blue');
desenhaCirculo (250,160,20,'yellow');
</script>
