Interlock bricks are made of cement with the addition of cement and sand, so they are made of cement at a lower cost than conventional bricks. In fact, interlocking bricks cost 35% less than conventional bricks. Interlock bricks may contain 10% cement, with the remaining mixture containing soil and sand. Interlocking bricks are an improved form of traditional clay bricks. Each brick is designed to seal itself to other surrounding bricks without the use of mortar. Automatic locking is achieved using the Shear key and the lock mechanism.