If you haven’t seen the Grow Cube before then you are lucky and I do apologize for bringing it to your attention. I realize that it’s been around for a while, but some may have missed it. [No thanks to Marc Rittle for the link.]
If you don’t have hours to kill then a search for grow cube solution on your favorite search engine should do the trick. But I doubt you’ll appreciate it if you don’t spend at least a bit of time trying to figure out the solution on your own. No comment as to how much time.