Okay you guys can do what you want but here's the deal
I respect what your trying to do but frankly there is a reason to using a ruler when drawing in perspective but I'm not going to go there. Secondly even when looking at yoitisi's example his box clearly converges away from the viewer, his construction lines are all there, for everything including ellipses...
I dunno who drew that boat, but the line weights are all the same. It looks wonky due to bad perspective. 1-2-3 reads are off but I don't care about that really.
That cast shadow is off in the back. Your better off just drawing a horizon line with VP's and doing it that way.
that door handle, okay I have no idea if that ellipse has a push mechanism, or what but frankly there is no arrows telling me what this made out of. 2nd of all when attempting this you would use a cut away to describe the turning mechanism, well that is being too critical but anyway same thing that box is not in perspective, line weights off, 1-2-3's off, ellipses way off. I'm done I got my own stuff I gotta deal with.
Don't wake me for the end of the world unless it has very good special effects