```.cpp Canvas c1; circle = c1.addCircle(blah); c1.addRectangle(blah); c1ircle.setColor(red); Canvas c2; circle = c2.addCircle(blah); c2.addRectangle(blah); SmartLeds.show(c1); SmartLefs.show(c2); blink(Circle& c) { if (millis() % 1000 < 500) c.setColor(red); else c.setColor(green); } c ... f = c.render() c.... e = c.render() e!=f frame f; drawCircle(f); drawRectangle(f); frame e; drawCircle(e); drawCircle(e) // ```