Upside down stairs in corner are placed 90 degree wrong.

Upside down stairs in corner are placed 90 degree wrong.

I think the images are quite clear, I'm placing the stairs at the cross.
To reproduce:
1, Place 2 stairs upside down next to the corner on a normal 90 degrees angle.
2, Place the corner peace and be amazed that you placed it 90 degrees wrong, every time