US Patent 7731149 Septic tank form

A casting mold including a first form having a first wall and a second wall, the first and second walls defining a first casting space. The casting mold further including a second form having a base and a wall extending from the base to define a second casting space. The second form is stackable on the first form portion such that the first and second casting spaces can be filled with a casting material when the second form is on the first form. The second form includes a port defining access into the first casting space such that the casting material can be disposed into the first casting space through the port.