Pour a small amount of mortar mix into a bucket. Create a deep pocket in the center of the mortar mix and slowly pour water into the pocket. Use a metal spatula or wooden broom stick to stir in the water and mortar mix. The mortar mix should become like a thick paste.
Pour the mortar mix into either the pie tin or the pizza box, depending on your shape and size preference.
Use the metal spatula to smooth out the mortar mix. The surface should appear smooth and flat.
Allow the mortar mix to harden up to approximately five minutes.
Add decorative items such as marbles, beads and tile pieces as the mortar begins to harden. Press the decorative item into the mortar mix to ensure it is flat with the surface.
Allow the mortar mix to harden up to approximately five more minutes.
Using a plastic knife or a pencil, begin writing or drawing on the surface of the mortar mix.