Sad news to report, the death of Otto Piene.
Piene was a giant of the post-war modern German art scene, and renowned for his enormous often illuminated, open-air sculptures that made extensive use of technology. One of his most famous pieces was the huge illuminated Rainbow, unveiled at the end of the 1972 Munich Olympics.
As well as his mastery of lit sculptures he was an exponent of Rauchbilder (smoke pictures), where pigmented paper is set alight and the resulting soot used to create images.
There is an obiturary to Piene here:
and you can see some of his work here on Vimeo: