These belong to my grand-daugter, given her by a friend for Christmas. Smashing aren't they? Their shape, their colour ... and they are hollow and stack one onto the other.
They don't write on walls. They can't write on floors. They only write on paper. From what I have read, they were designed in Australia. Notice that: designed! That probably meants they are manufactured in that area north of us whose century it is going to be. Go get some. You will love them.
Now I have to remember to get another scrap book, as our current one is full to the gunnels.