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  • Writer's pictureFACTORALY


Updated: Sep 19, 2023

Let's start with the world's most famous Cypher. Here's an Enigma Machine. You can see a real one at Bletchley Park.

And here's how it works:

Know your bits from your bytes...

Know your Morse...- - -

Hobo Codes



Yellow traces on the pavement denote gas. The amount of information sprayed in yellow depends on the nature of the subsurface gas service routes. The most common information offered along with spraying for gas pipe locations is either HP, MP or LP, meaning High Pressure, Medium Pressure or Low Pressure respectively.


As you might expect, red is associated with danger, so it’s no surprise that red denotes electricity, specifically service routes that carry it. Unquestionably, it would be very dangerous to strike an electricity cable, which is why it is essential to map out underground service routes before any intrusive construction process occurs. H/V means High Voltage and L/V means Low Voltage, S/L means Street Lighting.


Blue paint is used for water supplies. If a water pipe is struck in the early construction process, you can have major problems. Earlier this year in the West Midlands an entire street was plunged underwater by a ruptured watermain following a pavement excavation.


In terms of utility tracing, green paint (used for “comms” or “telecoms” cables) has become a much more popular colour over the past decade or so. There’s a simple explanation for this: broadband. In today’s world disruption to comms services can be very disruptive (particularly for businesses) so understanding their precise location when laying new services is crucial.


White is the universal colour used for comments, annotations and notes sprayed onto the pavement, white lines, or more commonly words generally accompany any colour that needs annotating to clarify meaning or to underline certain information.

Test the strength of your password:

What Three Words

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