Umm, why do you assume there is such thing? Have you seen such thing made by someone so that it works too? Why would you use popsicle sticks to make a puzzle box? To me this just seems like not very well thought idea.
I saw one onyoutube but it just showed how the puzzle works, it didn't show how to build one. Popsicle sticks are of same sizes so building a puzzle made of it is possible same as building a lego puzzle. Instead of using wood (which is more expensive for me) I found an alternative way to build a puzzle box an that is using a popsicle sticks but I can't find a plan for it.