Piezoelectricity was the generation of electricity from certain rocks or crystals. Hsien-Ko Chang's criminal gang applied piezoelectricity to their operation in the 1930s, using crystals to open the Dragon Paths so they could travel instantaneously around the world. Installing generators into a mountain, Hsien-Ko planned to create enough energy to interrupt the zygma beam and make Magnus Greel's time cabinet arrive in 1937. (PROSE: The Shadow of Weng-Chiang)