epresent a _Grey_ Counter (this may be interpreted to mean "There is
_nothing_ here").

The Pair of Propositions, that we shall have to represent, will always
be, one in terms of x and m, and the other in terms of y and m.

When we have to represent a Proposition beginning with "All", we break
it up into the _two_ Propositions to which it is equivalent.

When we have to represent, on the same Diagram, Propositions, of which
some begin with "Some" and others with "No", we represent the _negative_
ones _first_. This will sometimes save us from having to put a "I" "on a
fence" and afterwards having to shift it into a Cell.

[Let us work a few examples.

(1)

"No x are m';
No y' are m".

Let us first represent "No x are m'". This gives us Diagram a.

Then, representing "No y' are m" on the same Diagram, we get
Diagram b.
pg051
a b
.---------------. .---------------.
|(O) | (O)| |(O) | (O)|
| .---|---. | | .---|---. |
| | | | | | | |(O)| |
|---|---|---|---| |---|---|---|---|
| | | | | | | |(O)| |
| .---|---. | | .---|---. |
| | | | | |
.---------------. .---------------.

(2)

"Some m are x;
No m are y".

If, neglecting the Rule, we were begin with "Some m are x", we
should get Diagram a.

And if we were then to take "No m are y", which tells us that
the Inner N.W. Cell is _empty_, we should be obliged to take the
"I" off the fence (as it no longer has the choice of _two_
Cells), and to put it into the Inner N.E. Cell, as in Diagram c.

This trouble may be saved by beginning with "No m are y", as in
Diagram b.

And _now_, when we take "Some m are x", there is no fence to sit
on! The "I" has to go, at once, into the N.E. Cell, as in
Diagram c.

a b c
.---------------. .---------------. .---------------.
| | | | | | | | |
| .---|---. | | .---|---. | | .---|---. |
| | (I) | | | |(O)| | | | |(O)|(I)| |
|---|---