| _____|_____ |
| | | | |
| | 1 | 0 | |
| | | | |
-------------------


This tells us, with regard to the xy'-Square, that it is wholly
'empty', since BOTH compartments are so marked. With regard to
the xy-Square, it tells us that it is 'occupied'. True, it is only
ONE compartment of it that is so marked; but that is quite enough,
whether the other be 'occupied' or 'empty', to settle the fact that
there is SOMETHING in the Square.

If, then, we transfer our marks to the smaller Diagram, so as to
get rid of the m-subdivisions, we have a right to mark it


-----------
| | |
| 1 | 0 |
| | |
-----------


which means, you know, "all x are y."

The result would have been exactly the same, if the given oblong
had been marked thus:--