Homemade Chalk - cooking recipe

Ingredients

6 egg shells
1 rock
1 tsp. flour
1 tsp. very hot tap water

Preparation

Wash and dry egg shells.
Use rock to grind egg shells into powder.
Put powder in a dish.
Measure and combine flour and hot water in another dish.
Add 1 teaspoon of the powder.
Mix and mash until mixture sticks together.
Shape and press into a chalk-stick shape.
Roll the stick tight in a strip of paper towel.
Dry for 3 days, until hard as a rock.
Write with the chalk.
Erase with your shoe.