Example written in answer to the question Click How to superimpose pages from existing documents into another document?
superimpose
##GITHUB:https://github.com/itext/i5js-sandbox/blob/master/src/main/java/sandbox/stamper/SuperImpose.java##
Results
https://github.com/itext/i5js-sandbox/blob/master/cmpfiles/stamper/cmp_primes_superimpose.pdf