The two motor driven "mobiles" which I am exhibiting [August, 1933] are from among the more successful of my earliest attempts at plastic objects in … - Alexander Calder

As truly serious art must follow the greater laws, and not only appearances, I try to put all the elements in motion in my mobile sculptures.

My entrance into the field of abstract art came about as the result of a visit to the studio of Piet Mondrian in Paris in 1930. I was particularly impressed by some rectangles of color he had tacked on his wall in a pattern after his nature. I told him I would like to make them [Mondrian's flat painting] oscillate, he objected. I went home and tried to paint abstractly - but in two weeks I was back again among plastic materials.

I say nuclei, for to me whatever sphere, or other form, I use in these constructions does not necessarily mean a body of that size, shape or color, but may mean a more minute system of bodies, an atmospheric condition, or even a void. I.E. the idea that one can compose any things of which he can conceive.