If you get inspiration from another designer and yet you change it drastcially, add your own spin, style etc when does it become your design and not a version of theirs?
This is such a great question.
I think any "change" that would deviate from the original would technically make it your interpretation of it.
I think it would be your own if you could look at the cake and not see the other cake. Such as if I saw the two side by side, and I wouldn't guess that oh, this cake design is from that cake.
Personally I get ideas from many different places, so most of my cakes can be two or three or more different ideas combined. I do believe that it is hard to come up with something completely orginal that hasn't been done before, so I think that a good portion of cakes out there are inspired from others.