Chalk One Up: As an action, you can use this chalk to draw a simple symbol. A creature using this chalk must have at least an intelligence of six (6). You can draw up to 20 symbols with this chalk before it is completely used up.

Square: Fills a container with 1 pint of your favorite ale.
Circle: Casts the Light Cantrip on the object it's drawn on.
Triangle: Fills a container with 1 pint of lamp-oil.
Cross: Casts the spell Grease when a creature crosses the symbol. Lasts for 8 hours maximum, the DC for this spell is 12, A maximum of 3 cross symbols can be active at a time.