Using struct instead of enum for shapes

[TornaxO7]

Hi, I've got a little suggestion here for the Shape enum.

In my opinion each shape should be a struct and not an enum-entry. Reason: Each
enum has its own functions. If we take a look into the methods of the enum, we
can clearly see, that each enum entry has the "same" functions but with a
different implementation => This can be done with a trait!

What do you think? @flxzt

Edit 1

Wait a minute, I just see, that the Shapes are already implemented as a struct. So the enum is just for easier matching?

[flxzt]

That pattern is used to store different types in a collection, without using trait objects and dynamic dispatch.

[TornaxO7]

hm... ok, I thought that it would be better if we use the trait objects directly but I think it's fine