During one of my Pinterest wanderings where I sit and drool and become glary-eyed and sometimes go into an eye-candy coma (don't laugh you know you do it too) I saw this site. You might have seen it too. But I have gone crazy doodling these repeat pattern stacks. There is a help sheet in the site so you can do it. It is extremely easy and so fun so... go do it!
You'll thank me for it later!