I saw this idea originally over at Confessions of a Homeschooler and knew it would be a great craft to do with the boys.
We tackled this at the end of a preschool unit at the beginning of February and the boys loved it. I think they loved it most because we got to use "blue!" (I.e. glue hahaha)
You will find a full list of supplies through the link above but this is our version!
This is such a fun easy project for the kids and, depending on their ages then can do more (or less) of the project on their won.