Conception is a lithograph dated around 1968, an artist's proof from an edition of 75 copies, which Alexander Calder gave to Eusebio Sempere with a handwritten dedication at the top: "Sempere, sempre". The play on words between the Alicante artist's surname and the Catalan adverb "sempre" reflects the friendship that united both of them and adds to the work a value that goes beyond the strictly artistic.

The composition is of great formal simplicity based on sinuous lines and flat color fields. Three elements and three primary colors. The undulating black figure introduces rhythm and movement, while the contrast with intense red and blue generates a dynamic visual balance. It is Calder's characteristic language in his graphic work: biological and fluid forms, flat and direct color, balance between tension and rest: minimal elements, simplicity of lines and primary colors. The same principles that govern his mobiles are transferred here to paper with identical economy of means.