Ronnie has created two prisms out of plywood for a planter box. He cut wood to build a planter that is 6 in tall, 12 in wide and 8 in deep. He realizes that one cube is slanted slightly while the other one is has right angles as shown in the images below. He is worried that the slanted prism will hold more soil that the right prism. If the measurements of the edges of the prisms are the same, what is the difference in the amount of soil the planters will hold?