all deep cut puzzles ( that do not have other cuts) can be made any size, and still be proportional.
for example: 2x2, 24 cube, penultimate, chopasuarus, skewb, big chop
When I first read this I wanted to state:
"That's not even all yet.
All deep cut puzzles can be extended to any size and also put into any shape without additional parts beeing needed.
You can put a pentultimate mech into a cube if you want..."
But now that I think of it, a 3x3x3 can put into any shape to, BUT if you extend it the pieces are not proportional anymorel.
So my statement is actually a reduction of yours.
So what you said stays the bottom line and most important point here, as well as essential propertie of deep cut puzzles.
All puzzles, where all existing cuts have completely crossed already before or exactly at the boundaries of the body they are embedded in, can be extended to any size or shape without additional parts beeing needed.
Deep cut puzzles ( that do not have other cuts) can be made any size, and still be proportional.
Last line is yours.
I just still wanted to share these thoughts here, even after seeing that my "additional info" is not really additional.