They were also one of the biggest, and best-sounding, examples of the idea that the audience should participate in the music. Träd, Gräs och Stenar was formed in 1969 by drummer Thomas Mera Gartz, bassist Torbjörn Abelli, cellist Arne Ericsson, and guitarist Bo Anders Persson, remnants of International Harvester, and released a self-titled debut album in 1970. That same year they wrote the music for the film Du Gamla du Fria but remained mainly a live band. Not only did they perform better live than on record -- they even had a program that pointed out live interaction with the audience as the main purpose.