ALWAYS
LEAVE A GAP

Three urinals, 762 mm on centre. The left one has been taken since May 1976.
Pick yours.

UNCHOSEN two ends, one middle. the middle is the gap.

CAPACITY: 2 of 3
THE GAP: 762 mm . UNFILLED
GAP COST: 0.1 s

Micturition timed at three interpersonal distances. Middlemist, Knowles & Matter, 1976, n = 60.

THE MEASUREMENT

In May 1976 three psychologists stationed a confederate at the middle urinal of a three urinal lavatory, put a bucket, a sponge and a sign reading "don't use, washing urinal" on the right hand one, and hid an observer in a toilet stall behind a periscope built into a stack of books. Sixty men were timed to a tenth of a second, and none of them were asked first.

MICTURITION AT THREE INTERPERSONAL DISTANCES . MIDDLEMIST, KNOWLES & MATTER, 1976 . n = 60
CONDITION	DELAY OF ONSET	PERSISTENCE	TIME AT THE WALL
nobody beside you	4.9 s	24.8 s	29.7 s
one urinal between	6.2 s	23.4 s	29.6 s
shoulder to shoulder	8.4 s	17.4 s	25.8 s

Delay and persistence are one number. A man spends 29.7 s at the wall alone and 29.6 s with a fixture between him and a stranger, which is the same number to anyone who is not holding a stopwatch. Shoulder to shoulder it falls to 25.8 s, because he starts 3.5 s later and stops 7.4 s earlier. That is the whole argument for the gap: it is free, and closing it costs 3.9 s.

The pilot run watched 48 men pick a urinal with no confederate and no sign. Not one of them chose the position beside another man. The paper went on to become a standard teaching case in research ethics, which is the other thing that happens when you measure something nobody agreed to.

THE MAN LAWS

Five clauses, sandblasted into the tile. Four of them are quoted from a plumbing code or a peer reviewed paper. Nobody wrote the fifth one down until an advertising agency did.

405.3.1THIRTY INCHES ON CENTRE.762 mm between adjacent fixtures, and not less than 381 mm to a side wall. Closer than that is not a men's room, it is a queue.
FUN 2010TAKE AN END.Kranakis and Krizanc modelled it and printed the sentence: choosing an end position is to your advantage for all n.
n = 3NEVER THE MIDDLE OF THREE.An end saturates the wall at two men. The middle saturates it at one. You do not lose the gap, the room does.
2903.1.5THE SCREEN STARTS AT 305 mm.A partition may begin no higher than 305 mm off the floor and must reach 1524 mm. It became code in the 2009 cycle. Men had the rule 33 years earlier and never wrote it down.
FIFTHIF BOTH ENDS ARE GONE, WAIT.Take a stall. Wash your hands slowly. Come back in five minutes. Waiting has never cost a man anything the middle would not have cost him twice.

STALL 01 . CLIMBING WALL

HE TOOK THE MIDDLE ONE

The holds behind you sit 400 mm apart because a hand has to reach the next one. Every distance in this building is somebody's opinion about how close is too close, and only one of them is not printed anywhere.

In the pilot study, 48 men were watched choosing a urinal. Not one of them picked the position next to another man. 48 out of 48, no sign, no fine, no code section.

STALL 02 . THE COURT

GAP UP, NEVER FILLED

A gap on a chart is a price nobody traded at, and the whole trade is that it usually gets filled. This one is 762 mm wide and filling it is a criminal offence in every men's room on earth.

TICKER: $GAP
ON CENTRE: 762 mm
THREE POINT ARC: 6.75 m
WALL SATURATES AT: 43.23%

Fill a long enough wall with men who all obey the code and it tops out at one half minus one over two e squared, 43.23 per cent occupied. The other 56.77 per cent of every men's room is gap.

STALL 03 . MARBLE

FREEMAN URINAL