American [[Minimalism|Minimalist]] and [[Process Art|process]] sculptor born in 1938 in [[San Francisco]], [[United States]]. His massive, site-specific works in weathered Cor-Ten steel — torqued ellipses, tilted arcs, and serpentine curves — radically transformed viewers' experience of space, weight, and bodily perception. Late works distil his vision to elemental form. Died 2024.