>>16762503
dude, you can, and it takes 3 objects.

let x be the height of the overall cube.
have a square prism of sides [(x-1),(x-1),x].
on one rectangular side, add a prism of sides [1,(x-1),x] so that a shape of sides [x,(x-1),x] is formed.
finally, add a prism of sides [x,1,x] to a side of the prior shape, of sides [x,x], to form a shape of sides [x,x,x]
qed

i get why people didnt answer your question before