An engineering drawing in white line on green: a VR headset at the right, fed by two tubes that run back through a bank of valves, a pressure gauge and a large cylindrical manifold labelled reflator. A title block in the corner reads Series of Tubes Ltd, drawing ST-7, not to scale.
Technical briefing No. 7 · Revised

Virtual reality is a series of tubes.

For some considerable time now, work has been under way to bring the virtual world to a state of reasonable tubularity. Series of Tubes Ltd has been responsible for the tubes since 1974, which predates virtual reality by some margin and has never once been held against us.
Section 1

The basic principle

When you put on a headset you are not, as is widely believed, entering another world. Another world is being delivered to you, through tubes. It travels folded flat for economy, is unfolded at the eye end by the polyhedral reflator, and is then presented to each eye separately, so as to avoid an argument.

The original apparatus had a single tube. It worked well, but only in one direction, and early visitors frequently arrived in a world without any means of leaving it. The bidirectional tube was introduced in 1981 and has been fitted as standard ever since. Nobody has asked what became of the early visitors, and we have not volunteered it.

A labelled cross-section of a single tube. A folded world travels left to right past a row of perforated latency baffles, through a quaternion grommet and an occlusion bung, and out through a tapered frustum sleeve towards an eye. A narrow voice tube with a small brass flap runs along the top.
Fig. 1. The standard tube in section. The world travels left to right. The voice tube runs along the top and is not to be used for the world.
2 Tubes per headset, one per eye
0.3 bar Working pressure, quiet lobby
11 bar Working pressure, Friday night
1974 Established, regrettably early
Section 2

Principal components

Each tube is made up of a small number of standard parts. None of them are serviceable by the user, and most of them are not serviceable by us either.

Part ST-7/1

The polyhedral reflator

Takes the incoming world, which has been flattened for transit, and restores each of its faces to the correct number. Early units now and then restored one face too many. The extra side is still visible in some older worlds if you stand very close to a wall and do not look directly at it.

Part ST-7/2

The quaternion grommet

Seals the joint between the head tube and the two hand tubes, so that rotations arrive in the order in which they were made. Without it, turning left and then looking up is indistinguishable from looking up and then being somewhere else entirely.

Part ST-7/3

Latency baffles

A row of perforated plates which hold the world back by about eleven milliseconds, so that it does not arrive before you have asked for it. Unbaffled tubes were trialled in 1988 and found to be upsetting.

Part ST-7/4

The occlusion bung

Prevents the parts of the world you are not looking at from coming down the tube at all. They are held in a reservoir directly behind your head and released the moment you turn round, which is why one should never turn round quickly.

Part ST-7/5

The frustum sleeve

A tapered collar at the eye end which gives the world its perspective. Fitted the wrong way round it makes everything enormous and very far away, an effect several worlds now charge extra for.

Part ST-7/6

The voice tube

A narrower tube along the top, with a small brass flap at the far end which the user may close at any time. This is the mute button. It was adapted from the ship's speaking tube in 1979 and has not been improved upon.

Section 3

Common faults and their remedies

Fault 3.1

Lag

Caused by a kink. Do not attempt to straighten the tube yourself. Stand still and allow the world to work its way through.

Fault 3.2

An avatar arrives grey

Its textures have become separated from its geometry in transit, generally at a bend. They will follow presently. If they arrive bright pink, they have come down somebody else's tube and should be returned.

Fault 3.3

Falling through the floor

The floor has not been fully decompressed. Remain calm, keep falling, and report to the spawn point when you get there.

Fault 3.4

One person is very loud

There is too much pressure in their tube. This is not a fault in your equipment and cannot be remedied from your end. See Part ST-7/6, the brass flap.

Further reading

That concludes the briefing.

Those wishing to go into the matter more thoroughly will find the full specification, with tolerances, on the following page.