https://media.ccc.de/v/emf2016-306-using-printed-circuit-boards-to-make-snowflakes The construction and programming techniques used to make a huge-scale lighting installation, with 84,000 LEDs, 25,000 PCBs and 14,000 PIC microcontrollers. Printed circuit boards were used as mechanical structure and electrical interconnection to make large but lightweight illuminated snowflake shapes. This installation was built as part of a Christmas lighting feature in a Hong Kong shopping mall in 2015 MIke Harrison