Group {
	children [
		Shape {
			appearance {
				material Material2D {
					emissiveColor 0.333 0.222 0.555
				}
			}
			geometry DEF BIG_CIRCLE Circle {
				radius 69
			}
		}
	]
}

FILE "ShrinkCircle.bif"

AT 12000 REPLACE BIG_CIRCLE.radius by 0.68
AT 20000 REPLACE BIG_CIRCLE.radius by 6.9