Marching tubas stumble, fall like dominoes

Chain Reaction - Domino Effect

The domino theory is one of several major theories concerning accident causation. Developed by the safety engineer H. W. Heinrich, it defines an "accident" as one factor in a sequence that may lead to an injury. Heinrich visualizes all relevant factors as a series of dominoes standing on edge; when one falls, the linkage required for a chain reaction is completed.