Consider for instance the first drawing : in my perception, the staircase has 4 steps because there are 4 horizontal levels. So the first step (ie the lower one) is made up with 4 blocks, the second with 3 blocks, the third one with 2 blocks and the fourth with 2 blocks again ; so the sizes of the steps are not in _strictly_ descending order (the sizes are 4 3 2 2).
So what does "size of a step" really mean? the number of blocks between two consecutive horizontal levels ? the height from the ground of a given level? the height between two consécutive levels?
"descending order" : how do you count the steps? from right to left? from top to bottom?
The task is no more than finding the number of partitions of n into at least two distinct parts.