Fourth Stone is related to a group of relief sculptures from the early 1960s in which Bontecou inserted serrated saw blades or metal bars into her signature holes. These blades and bars conjure isolated, floating mouths of razor-sharp teeth or prison cell windows. She also began to use horizontal stripes, reminiscent of prisoners’ uniforms. The effect is claustrophobic and threatening. Fear and violence often go hand-in-hand with wonder and the sublime for Bontecou, who once wrote that in her work she wanted to “glimpse some of the fear, hope, ugliness, beauty, and mystery that exists in all of us.”