A circular shape.
Circle(): Shape;
Circle()
.fill(Color("blue"))
.frame({ width: 100, height: 100 })
Circle()
.stroke({ style: Color("red"), lineWidth: 3 })
.frame({ width: 50, height: 50 })
ZStack([
Circle()
.fill(Color("green")),
Circle()
.stroke({ style: Color("black"), lineWidth: 2 })
])
.frame({ width: 80, height: 80 })