The other day I tripped across this news item - here's the link and a copy-and-paste of the first paragraph:
Mark Wallinger unveils labyrinth Tube art
Permanent art works are to be displayed at each of the 270 Tube stations to commemorate the network's 150th anniversary.
Inspired by the Tube's symbols, each station will have its own unique black and white design.
The first ten will be on display from 7 February.
It represents the journey through the network taken by millions of individuals each year from that place, Wallinger said.
I'm looking forward to hunting them down at some time - a Summer project, maybe.