Sometimes the impossible is possible. I have seen this cube done in many ways. The drawing is easy but I have seen this crate actually constructed. The one of real wood is very real looking, how was it done? Actually constructed? or a photoshop creation?
The box can be constructed as long as it is viewed from the proper angle. Continue further down the page for a few different real physical constructs of this illusion. The Lady holding the box below I found on Amazing Art.
Below is Jerry Andrus demonstrating his construction of the impossible crate and exposing how he accomplished this illusion. (Found on Amos Storkey's page)