I've wanted a diaper stacker for a while. It would be best to buy a used one, but I've had a hard time finding one. I also couldn't find a good pattern for one. It took a long time to make...but apparently it was worth it to me because I made a second one. These dimensions can be adjusted easily. One of them I made closer to 11x7 on the base, and shorter than 20 inches.
The last step is to cut out a piece of cardboard the size of the bottom and put it in.
I freed up some shelf space and didn't spend $25 on a new diaper stacker!