Mirror Images - Why aren't they reversed top to bottom?

I encountered this old puzzling question on xkcd: "When you look at things on a mirror, how come they're reversed left to right and not top to bottom? What's so special about the horizontal axis?" and decided to get to the bottom of it once and for all. So this is how it goes:

Mirrors actually show things as they are: left is left, right is right, top is top, bottom is bottom. The reversal actually occurs when you turn the object around to look at it in a mirror. Say you were holding towards you a cardboard with the word "CARDBOARD" written on it. Now if you wanted to look at it in a mirror, you'd have to turn it around, and that's the part where it gets reversed. People usually turn it around horizontally, so left becomes right and right becomes left. If the cardboard were transparent, then you would be able to see that you just turned the letters around horizontally with respect to yourself. So, if instead, you flipped the cardboard around top-to-bottom (try it), you would see in the mirror that the letters were reversed top-to-bottom, and NOT left-to-right. Now you might say "but that's because I made them upside-down!", but that's the point. Even in the "normal" case, you made the word right-to-left.

So what about words written on your t-shirt? You don't reverse your t-shirt around horizontally to see it. Well actually you do, when you wear it, as opposed to when you are holding it out in front of you. If you somehow wore your t-shirt by flipping it vertically and sliding the neck-hole down to your waist, then you would see the letters upside-down in the mirror.

Also, if you look at a word on a wall, and then turn around HORIZONTALLY to look at it in a mirror, then it's reversed left-to-right. On the other hand, if you turned around vertically by, say, doing a hand-stand, then you would see it reversed upside-down. Sheesh, all the ways this horizontal turning-around has crept into our lives! I guess it's because we're conditioned (by evolution and gravity, perhaps?) to regard objects turned around horizontally as the same as the original object (i.e. a tiger turned away from you is the same as a tiger turned towards you, albeit one may be a bit less dangerous). An object turned over on its head, on the other hand, seems to us as a bit odd.

...Then there's the question: what if you turned around diagonally? Can you turn around diagonally? Well, at least you can turn around a piece of cardboard diagonally, in which case, left would be up, and... gah, that's a question for another time!

On saying "you do the same"

    I have, on countless occasions, seen the use of (and used) the argument "you did <something similar> yourself" when one is confronted on a questionable doing. The main problem I have with this argument is that it works both ways. If A does something bad, and B does something similar, then we can have B pointing out A's poor judgment, whereupon A points out that B has done the same, or we can have it the other way round. Then the winner of the argument is merely a matter of who was stupid enough to make the first move. I suppose it is a type of ad hominem argument, whereupon you go after the accuser instead of justifying your deed / admitting your mistake. I don't think you should feel smug about winning the argument after doing that - the simple fact is that you both lost.

Buried Treasure

A rusty old axe chisels away
It chances upon an unnoticed cave
From whence there flows a dullish glow
And then a voice slowly exclaims:

Let it shine free,
Let it shine through me
Let it find, let it find, let it find...
Away from all this comfort shall this mind be.

No more solace in stubborn ways
For in unknown places at last I may
Find long-lost delights of olden days;
May this old soul rejoice, and rise from its grave.

A rusty old axe chisels away
To uncover, remove, and then replace
That part of a heart that wouldn't give way
With a smoldering flame, a wrinkled rose that wouldn't decay,
A fickle thought that shall not say nay.

Restless

Struck by lightening whenever I move
Nimble fingers held tight with glue
A mind that's jumping, bouncing pumpkins
This is not what I should do.

Slippery shoes on floors of ice
Hold on tight, I feel like mice
Chasing the breeze to the nearest cheese
This is not what you'd call nice.

Marching lice through a forest fire
Pricked by thorns while jumping higher
Swinging branches, tingling armpits
Definitely not what you'd desire.

I'm not tired, don't know why not
I've gotta do more, I can't stop this
Must lock myself and block my senses
Gotta knock myself out senseless
Restless, restless, restless, restless,
Restless, restless, restless, restless.

I have nothing to give, to anyone
I'm the poorest of souls.

Who am I?
I am one who would not
One whose essence it is to not
No never, I would not
I am nobody.

Today

I killed them away
In search of the light
Now I am but an empty shell
What light? Why seek? Why fight?