The shape of a KitKat is quite complicated. If you change all the angled faces into horizontal or vertical faces, then a two piece KitKat is an octagon based prism. A four piece KitKat is a 14-gon based prism. Without that approximation it is not even a prism since the cross-section is not exactly uniform at an end and in the middle.
The shape of a tin can is a cylinder.
convex
sphere
a washer
Type your answer here... what is the answer
Pentagon
toroid
A decagon.
Any shape is mathematical.
octagon
a cube or cuboid
A six-sided shape is called a hexagon.