Loving this: modern day smoke signals.
In the Memory Cloud, text messages from members of the public are being projected as serif type onto plumes of smoke in Trafalgar Square. It's all the work of brothers Stephen and Theodore Spyropoulos, from experimental architecture and design practice Minimaforms; arranged through the ICA.
The installation has been running for the past couple of nights, and you've got one more night to check it out: from 7pm until 9.30pm, Friday 10 October.
Totally worth a visit.