
Ono put up a piece of wood with a hammer hanging from a chain, and on the ground was a large bucket of nails. Viewers were invited to hammer nails into the wood in any way they desired. This picture is the original version, but the first time I saw it, it was more recent version, a piece of plywood 4x8 feet inset into a blackboard cart on wheels. It blew me away. I vigorously hammered a couple of nails into it at random locations.
This may not seem like anything revolutionary, but in the 1960s, conceptual art was completely new and shocking, and performance art was in its infancy. Ono shaped a radical shift in opinion about art amongst both critics and artists worldwide, yet her influence is rarely acknowledged today.