They have blackboards inside and out, and play with chalk all over the place, so I didn't think this would be such a thrilling activity.
I WAS WRONG!
We took it a step further and discussed shading with our fingers and using the broad side of the chalk.
But basically, they just wanted to go at it, as usual, and since this is a process not a product session, they got to do so.
They kept asking for more paper and to do it again.