This, for example, would have been a very tricky puzzle to create even for 2D now try to implent this in a 3D environment...
The creators of the game would have had to sit down for a while and design (with measurements and calculations) then they would have coded it to see if it worked, if not, back to the drawing board.
It isn't as easy as what you're trying to make it out to be, modeling scenery is one thing but modelling puzzles then adding back code is a totally different ball game.
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