In 1954, dissatisfied with the available brush cleaning systems that incurred damage to paintbrushes during washing, Zimmerman developed an alternative device he named “the Silicoil”. The invention of the Silicoil brush cleaning system was patented in 1962 and afforded Zimmerman the freedom to focus on pursuing his artistic vision. The Silicoil, manufactured and distributed by the Lion Company, Inc. in Louisville, Kentucky, continues to be one of the leading brush cleaning systems on the market today. Its design is one variation of the swirling, spinning, rotating movements Zimmerman frequently used to explore relationships between forms. It is these series of concentric circles, manifested three dimensionally in the elegant utility of the Silicoil, repeated in paintings such as Double Coil and Untitled #9 and evident in the rotating motion of the Slu Balls that thematically unites Zimmerman’s visual vocabulary.