How to make hollow cement bricks?

To make hollow cement bricks, you will need cement, sand, crushed stone, water, and a mold.
First, mix the cement, sand, and crushed stone together using a ratio of 1:2:3.
Next, add water to the mixture to create a workable paste.
Then, fill the mold with the paste and let it set for a few days until it’s hard.
Finally, remove the brick from the mold and voila – you now have hollow cement bricks!