Had when i worked in a preschool and kids love them! I would use colored sand instead of white salt. DIY salt tray with alphabet cards. Easy to make and kids have fun smoothing out the salt after correctly making the letter
DIY Kids space reading nook~ Rain Gutter Kid’s Bookshelves This could be the best 're-purposing' project I have seen so far.what a great idea and the books, or whatever, would not fall off the 'shelves'.