Classic RRP (Rita's Rump Pocket) pattern.

This pattern is a one-size fits most flannel fitted pocket pattern that does not have closures. It fits tiny babies to large toddlers and is very trim. It is a very simple fast diaper to sew up and you can find everything you need to make one at your local Walmart or fabric store. Did I mention that RRPs are also reversible? Use cute prints as the outer and the inner, and you have two cute looks with one diaper.

Above is the RRP on a baby and a toddler.

Here you can see how folding down the front of the RRP makes the rise shorter for smaller babies. The fleece covers pictured on here are made from the Mile High Monkeys pattern which I can't find any more.

Here is the free downloadable RRP PDF pattern.