A new book, Signs of Life, by Dave Askwith and Alex Normanton, features spoof signs which lampoon officious notices and labels that inform and instruct.
Advertising executive Dave Askwith took inspiration from his daily commute from Brighton to London. "It was mundane - my fault for sitting in the same seat, staring at the same signs."
For his own entertainment - and sanity - he devised personal variations on the signs and labels that are part of daily life.
"That's when Alex came in - he does typography and offered to make them look proper," says Mr Askwith.
Their first effort aimed to shed light on a mysterious lever on a slam-door train.
At first glance, the signs appear official...
... but on closer inspection are fanciful nonsense.
"It started as a hobby - I wanted to see how long they'd stay up," says Mr Askwith.
"Some lasted several weeks before being nicked, or taken down by disgruntled staff."