How so?

Because if it were in another, it would be encircled by that in which it
was, and would touch it at many places and with many parts; but that which
is one and indivisible, and does not partake of a circular nature, cannot
be touched all round in many places.

Certainly not.

But if, on the other hand, one were in itself, it would also be contained
by nothing else but itself; that is to say, if it were really in itself;
for nothing can be in anything which does not contain it.

Impossible.

But then, that which contains must be other than that which is contained?
for the same whole cannot do and suffer both at once; and if so, one will
be no longer one, but two?

True.

Then one cannot be anywhere, either in itself or in another?

No.

Further consider, whether that which is of such a nature can have either
rest or motion.

Why not?