I've always been a fan of pictograms. I was fortunate enough to get a job making hazard signage during my 20s, so I got to muck about with all sorts of dangerous-looking signs, with exploding chemicals and razor-sharp dogs and flammable doors.
What I like about pictograms is the simplicity of form that connotes meaning with a brevity of detail.
A sign with a simple fire on it means "this will catch on fire", without the need to explain how or why. And it's a lot more succinct than a sign saying "LOOK, JUST TRUST ME, THIS WILL CATCH ON FIRE, SO LEAVE IT ALONE, SAVVY?"
A skull and cross bones means death (followed by disintegration of most of your body, until all that is left is your noggin-nut and a pair of bones sitting in an economical pile).
There's an argument going on in international circles about EXIT signs, an article about which can be found here, but the crux is that the US EXIT sign is simply the word EXIT in red, while the internationally-recognised EXIT sign is a guy running out a door, printed in green.
The international version works much better for non-English speaking people, but the US are reticent to change to the international version, probably because they didn't make it in the first place. However, considering that Spanish is becoming the "language de-jour" in the US, it doesn't make sense to have your signage in only English.
The International EXIT sign: The front, and the rarely-seen back of the sign.
What does this have to do with a unicorn? Glad you asked...
Well, the unicorn (or unicorno is Spanish) is fast becoming the NEW international sign for exit, because let's face it, when you're in a dangerous, desperate or inhospitable situation (for example, eating a bomb sandwich, fleeing a rottweiler on fire or being Carl William's gym partner), you want a sign that is unambiguous, a sign that is an instantly recognisable signifier for its intrinsic meaning.
And if you, I, or anyone were running away from a flaming rottweiler with a bomb sandwich in its mouth, and you, I or they ran past a door with a picture of a unicorn above it, we (universal) would all think the same thing:
"WHOA! THAT'S PRETTY WAY OUT."
And you know what? It would be.
This is my best selling t-shirt so far. It's odd, because it was a simple idea that I had for years but never got around to producing until recently, and while I thought it was funny, I didn't think it would quite as popular as it has been.
Turns out someone else also had the same idea, but I like mine because... it's mine.
And I didn't rip off My Little Pony...
Oh Snap! Oh no he didn't?
Oh Yes, I did! Zing!