cb.circle(250.0f, 500.0f, 200.0f);
cb.circle(250.0f, 500.0f, 150.0f);
cb.stroke();
cb.setRGBColorFill(0xFF, 0x00, 0x00);
cb.circle(250.0f, 500.0f, 100.0f);
cb.fillStroke();
cb.setRGBColorFill(0xFF, 0xFF, 0xFF);
cb.circle(250.0f, 500.0f, 50.0f);
cb.fill();