Therefore the angle GDA is a right angle. (I know you think I'm
repeating myself, but you'll see what I'm getting at in a minute.)

_Therefore_--and this is the cream of the joke--therefore--really, I
can't help laughing--therefore _the angle CDA is equal to the angle
GDA!_ That is, the part is equal to the whole--which is ridiculous.

I mean, it's too _laughable_.

So, you see, your rose-tree is not in the middle at all.

In the same way you can go on planting the old tree all over the
bed--anywhere you like. In every case you'll get those right angles in
the same ridiculous position--why, it makes me laugh _now_ to think of
it--and you'll be brought back to dear old CE.

And, of course, any point in CE _except_ F would divide CE unequally,
which I notice now is just what you've done yourself; so F is wrong
too.

But you see the idea?

What a mess you've made of the bed!

BOOK I., PROPOSITION 20.

THEOREM.--_Any two sides of a triangle are together greater than the
third side_.

Let ABC be a triangle.