Let a "layer" or a "floor" be the placement of cubes adjacent to each other, in rectangular shapes.
Each layer has columns and rows.
1. Way: let one layer be 3 columns * 3 rows.
place 4 of these on top of each other
check the picture, 1 layer has 9 cubes, so 9 cubic units of volume. 4 of these on top of each other, make a prism with 9*4=36 cubes which means 36 cubic units of volume.
2. Way. Form only one layer, which has 6 colums * 6 rows (per each column)
3.Way. let 1 layer be 2 columns * 3 rows,
place 6 such layers on top of each other
4. Way.let one layer be just one cube. Place the 36 cubes on top of each other
