code: func (c Circle) Resized(radiusDelta float64) Circle {
  	return Circle{
  		Center: c.Center,
  		Radius: c.Radius + radiusDelta,
  	}
  }
docs: // Resized returns the Circle resized by the given delta.  The Circles center is use as the anchor.
  //
  // c := pixel.C(pixel.ZV, 10)
  // c.Resized(-5) // returns pixel.Circle{pixel.Vec{0, 0}, 5}
  // c.Resized(25) // returns pixel.Circle{pixel.Vec{0, 0}, 35}