We have had our set of Stack n Smile Photo Blocks for awhile now, and I always want to use them for learning activities, but never get around to filling their sides with "stuff." I was putting together a game for Juliette and realized the cubes would work perfectly, but ahh I did not have the time to format a page on my word processing program with the letters I needed then cut them out and put them in the cubes. That's when I realized POST-ITS !!!! I was able to quickly write the letters on each post it and they were the perfect size to slide right into the pockets. I am so excited for all the fun learning activities that we can now quickly put together.