Cubes to squares puzzle

Here's a little puzzle we tried in 4G. We made three cubes with Cuisenaire rods: a 1 x 1 x 1 cube, a 2 x 2 x 2 cube and a 3 x 3 x 3 cube.
Then, once we'd made them, we made a square with all the Cuisenaire rods that we'd used to make the cubes.

Here are some pictures:

the cubes

Then we made a 4 x 4 x 4 cube. After that, we added the fours we'd used into the square:

Then, some of us tried with five:

 Here's all the pictures: