OMG... have you seen Crayola Crystal Effects Window Markers yet?? They are AMAZING!! If you have a sliding glass door or any reachable window for that matter, you can't live without these things! In fact I'd probably say that you are depriving your child by not having them!
Packaging says "Colors Crystallize Like Ice", and sure enough they do! It's the coolest thing ever to watch too. You, or your child if you're willing to share just draw on the glass and within a few seconds (sometimes a few minutes depending on Florida humidity) they start at one end and crystallizes until it reaches the other end!
The packaging says 8 years + , website says 4 years + (Good Consistency!) but my 2 and a half year old has proven pretty competent! I have yet to find them on the Ultrasuede couch located steps away. With that said, I will say I've seen a trial run done on the tile below the sliding glass door! Rest assured... it wipes right off with a little window cleaner! It also recommends a dry window and use in a dry climate, but I didn't let that stop me! Not however a great rainy day lifesaver!
Go directly to the store and buy these!!! Gave them as part of a Art Themed B-Day gift for a 2 year old, and got a text that night letting me know how much they loved them too!!!
Wal Mart link to check them out ; ) Ur Welcome!
Do it & MAKE IT FUN!!!