I found this image at instructables.com as part of a demonstration of 'How To Make The Cube Eraser Puzzle'. There the image is the other way up - I strongly suspect it to have been taken at a strange angle or published upside down. Either way, I prefer it this way up.
Looking into this puzzle, I find that there have even been videos posted online demonstrating how to do solve it. I must get one sometime and see if it really is as hard as all this proffered help seems to suggest.