From the Youtube description:
At the Arab Museum of Modern Art in Doha, Qatar this week, Chinese artist Cai Guo-Qiang put on his largest "explosion event" of the last three years, utilizing microchip-controlled explosives to form incredible designs and patterns. The video we've embedded of the event is an impressive testament to how a volatile black powder explosion can be controlled and shaped by computer.
Each set of explosions was calculated to paint a different picture. One series of explosions created black smoke clouds that looked like "drops of ink splattered across the sky."