Vertical Constellation with Bomb by Alexander Calder

Alexander Calder in his Roxbury, Connecticut, studio, 1941, The Alexander and Louisa Calder Foundation, New York

Calder is perhaps best known for his mobiles and stabiles. In numerous interviews, he described the delicate and precise mechanical process for the construction of a mobile, beginning with the smallest elements and working toward the larger ones. For each part he made constant adjustments, finding the perfect point of balance to ensure the greatest possible motion.