At Misu s Ice Cream Parlor, their famous 4-layer ice cream cake consists of four

At Misu's Ice Cream Parlor, their famous 4-layer ice cream cake consists of four layers of ice cream alternating with layers of cake. If there are 8 flavors of ice cream, and we count
different cakes based on the order of ice cream layers from top to bottom:
a) how many different cakes can be made if flavors can be repeated?
different 4-layer cakes can be made with repeating flavors
b) how many different cakes can be made if flavors cannot be repeated?
different 4-layer cakes can be made without repeating flavors