A few months ago I helped with a baby shower and I made a diaper cake for one of the decorations. Here is how I did it.
to form the top of the diaper cake take a diaper (newborn size works best) and start at the opening of the diaper and roll it. Take a rubberband and wrap it around the center of the rolled diaper to keep it from unrolling.
This forms the center of the top layer. You can also use a baby bottle or a bottle of baby shampoo for the center as well.
Add 7 more diapers to the rubberband. This completes your top layer
For the middle layer make a top layer again as instructed in the previous steps and then add 15 more rolled diapers to the rubberband. This completes your middle layer.
For the bottom layer I used a bottle of baby shampoo for the middle of the layer and then I made a middle layer around the shampoo and then added 15 more diapers to make the bottom layer.
I then used a cake platter I got from the dollar store to place my diaper cake on.
I then decorated the cake with ribbon to help hide the rubberbands.
Then I added some toys to dress it up more. The finished product! It makes a nice decoration and a gift as well. :)