Rectangle(width=100, height=100, color='black')
Ca=Circle(width=98, height=98, color='darkorange')
Cb=Circle(width=86, height=86, color='red')
Cc=Circle(width=74, height=74, color='purple', transparency=12.5)
Cd=Circle(width=62, height=62, color='lime')
Ce=Circle(width=50, height=50, color='silver')
Cf=Circle(width=40, height=40, color='goldenrod')
Cg=Circle(width=30, height=30, color='red')
Ch=Circle(width=15, height=15, color='green', x=10)

with animation(duration=10):
    Ca.color = ['darkorange','aqua']
    Cc.color = ['purple','darkgreen']
    Ce.color = ['silver','navy']
    Cg.color = ['red','darkviolet']
    Ch.x = 100