Soda Stream Carbonated Bottle Rack

So, we love our soda stream (with brand name syrup....5 to 1 mix ratio) and the original (new) carbonated bottles come in a nice SQUARE box for easy storage....
But, when you return them to the store for an exchange.... all you get is the bottle.... no box. (yes, I know i could have saved the boxes.... but that just didn't happen).
So, we made a rack to "pyramid" stack six refilled bottles in the upper cabinet.... without the fear of them coming down on someone's toes!
I work in inches, so