An interactive streetlight that records the shadow of a passerby and plays it back to the next pedestrian is among this year's Designs of the Year nominees (+ movie).
The streetlight looks like a normal piece of street furniture, but has an infrared camera hidden inside its head, as well as a lamp that projects a pool of white light onto the pavement below.
The camera records the shapes created by the movement of anything that passes through the pool of light – including people and animals.
These are processed by a computer and then projected back onto the ground as a solid dark image when something else passes through, creating an artificial shadow effect.
"It creates pockets of memory in the street; capturing your shadow as you pass underneath the streetlight and echoing it back to accompany the next person who passes by," said the designers in a statement.
"It compresses time within a single space to form a connection between those who inhabit the same urban environment," they added.
When there is no interaction with the streetlight for a prolonged period of time, it will enter what the designers refer to as "dream state", looping through previous recordings until somebody walking beneath re-triggers the camera and new footage is captured.
The duo originally came up with the idea of an interactive streetlight for an entry to the Playable City Award – an annual commission granted by local arts organisation Watershed that aims to promote ideas for making cities more enjoyable.
It was installed in eight locations on the streets of Bristol for two months in 2014 after winning the award.
"As well as animating some of the city's lesser-travelled nooks and crannies, Shadowing offers an exploration of the disconnectedness that technology can create between strangers, the role of light in shaping a city's character, and the unseen data and surveillance culture that pervades today’s urban spaces," said a statement from Watershed.
The camera and projection technology were housed in streetlights provided by the local council.
Shadowing is one of 76 projects shortlisted across six categories for the Design Museum's Designs of the Year awards and is on show at the accompanying exhibition at the museum's gallery in Shad Thames until 23 August.