I am not sure if I was around or visited WOX at that time or perhaps I only had a quick look. WOX looks great, with a topic and has a face of it's own but to me it's overwhelming as well. Perhaps not if I still would have my photocameras and was taking photos like I used to do (in a way I still am because if I go out I stand still and click with my children make ask: Are you taking a photo again!).

We can use concrete, gips, and indeed chalk. I did it many times and with a bit wafter it looks like watercolour and it can be saved with hairspray, coal from the woodfire is an option, lipstick, tea, coffee, and so on.

Perhaps it's good to teach something like this and show how to paint with different materials?
Sand can be "glued" on paper as well to make a drawing, and dried flowers, leaves, and grass, are great for making paintings. It's what we already learn as a toddler.