If you assume, that it is not draw box from-to, but draw a box with start-coordinates and 3 length values of the edges it would be for your values:
julia> scene = mesh(Rect3D(((-1,-1,0), (2,2,0.1))), color = "green")
julia> mesh!(scene, Rect3D(((-.25,-.25,0), (0.5,0.5,0.11))), color = "yellow")
Bit I didn’t look for details, just tried it.