Humans invented 'ceilings' so that stuff wouldn't fall on their heads. The ceilings then required 'walls' in order that they themselves wouldn't fall on people's heads. Unfortunately, the walls presented the problem that people couldn't walk through them, and so the 'hole' was invented.
It is a measure of the sheer bloody-minded contrariness of humanity, that having gone to all this trouble creating perfectly good holes, they go and put something right where you're trying to walk through. This is called a 'door'.
This guide entry is a brief guide to doors, and how to use them.
The most basic type of door, this consists of a large rectangle1 of solid material on a hinge, usually but not always the same size and shape as the hole it is blocking up.
Method of use: Walk up to door. Pull on handle. Pull harder. Swear. Kick door. Read sign. Push. Walk through. Look embarrassed.
The same as push doors, only the hinge operates the other way.
Method of use: Walk up to door. On basis of experience with previous push door, push on handle. Push harder. Swear. Kick door. Read sign. Pull. Walk through. Look even more embarrassed.
Akin to push and pull doors. Much used in hospitals, to keep them in business. Hinge swings in both directions.
Method of use: Walk up to door behind someone else. They push door open, you follow them. Get struck very hard on head, hand, arm or leg by violent swinging back of door. Look hurt, and very, very embarrassed.
A more complex way of blocking holes, this usually involves four doors mounted on a central axis, which rotates.
Method of use: Walk up to door. Try to get into hole, but be prevented by perilous spinning doors. Finally sneak in. Find you are unable to get out again. Continue being spun round by doors until thrown out of hole by centrifugal force. Look hugely embarrassed.
A mechanical door which opens by itself when people approach. It senses when a person walks up to it, and also seems to senses when the person believes the door will open. It always seems to respond in one of two ways. It either opens very quickly before the person expects it to, thus scaring them, or opens a considerable period after they expect it to do so, causing them to walk straight into it. Doors which respond in this second way are usually transparent, both so that the person walking into it doesn't realise that there is anything there and so that people on both sides of the door can laugh at the person.
It is interesting to note the new trend to affix signs with large black letters saying 'Automatic Door' to this type of door. This is not an attempt to educate any toddlers using the door, nor to point out the patently obvious fact that it is an automatic door. In fact they are usually there to alert people2 to the fact that they are walking towards a large sheet of glass.
Method of use: Walk up to door. Fail to anticipate time of opening correctly. Look indescribably embarrassed.
Revolving Automatic Doors
A dangerous combination of the two previous types of door.
Method of use: Walk up to door. Sneak into hole before slowly revolving door traps you. Find yourself in a small rotating gap between two doors. In order to speed it up, push on door in front of you. Sometimes the whole machine grinds to a halt, and in the most advanced ones a small mechanical voice says 'Automatic doors3. Please do not push. Please step forward.' Look frustrated. And embarrassed.