Alexander Calder's sculpture 10-5-4 embodies evidence of both Modern and Postmodern artwork. Much like his extensive collection of work using hanging mobiles, the simplistic shapes and minimal framework in this piece exude a surreal abstract form, yet hints at resonating nature, namely celestial bodies and leaves on a tree. Influences to his work range from the pioneering effort to sculpt using such a unique form as the kinetic mobile, a deep interest in understanding the Universe, and collaborating with other like-minded artists including Joan Miro.
Link to image of referenced artwork: https://theartstack.com/artist/alexander-calder/artwork-10-5-4-1958
In attempting to understand the motive for Calder's use of mobiles as vehicles for his sculptural artwork, French philosopher and critic Jean-Paul Sartre speculated that "his mobiles signify nothing, refer to nothing other than themselves," which echoes the characteristic of Modernism that the work stands alone and separate from the world around it. One can look at Calder's 10-5-4 in its isolated form, align the number of simple, colored shapes with its namesake and watch the pieces sway slightly in any minor flux of air. It becomes a wonder in itself without having to rely on external influences or context. The innovative qualities of the mobile as a sculptural form also exemplify Modernism by focusing on the technical expertise to engineer the form and the used materials. However, "as mobiles swept through commodity culture in the mid-1950's," the challenge arose to distinguish Calder as the innovator behind the mobile. This avant-garde initiative may have been caught up in a world of replicas and kitsch mobile art, but the ingenuity strengthened the association of Calder to pioneering mobiles as a unique art form, another facet of Modernism.
The alignment of Calder's 10-5-4 to Postmodernism stems from a reference to nature in its notion of a celestial body floating overhead and dynamically changing ever so slightly. He was "a key proponent of acentric, 'stellar' designs," which became a framework for his interpretation of the Universe in many of his mobiles and other sculptures. These imaginative visions of constellations and the like manifest the qualities of Postmodernism. At the same time, Calder and his close colleague Joan Miro "were influenced by the Surrealist notion of the unconscious as the most authentic source of inspiration, but they rooted their fantasies in recognizable imagery based on personal experience." The sculpture's title may appear enigmatic as to its true meaning, but the inspiration of natural phenomena in Calder's 10-5-4 is undoubtedly recognizable. As another nudge towards Postmodernism, the aforementioned dichotomy between independence of and dependence on context attests to its overlapping presence as Modern and Postmodern art. Both the isolated abstract form of the mobile and its semblance to a constellation or leaves on a tree become prominent forces battling to take precedence in the eyes and mind of a viewer.
 Alex J. Taylor, "Unstable Motives: Propaganda, Politics, and the Late Work of Alexander Calder," The University of Chicago Press Journals 26, no. 1 (Spring 2012): 25, JSTOR.
 Alex J. Taylor, "The Calder Problem: Mobiles, Modern Taste, and Mass Culture," Oxford Art Journal 37, issue 1 (March 2014): 27-45, https://doi.org/10.1093/oxartj/kct044.
 David Barry & Claus Rerup, "Going Mobile: Aesthetic Design Considerations from Calder and the Constructivists," Organization Science 17, no. 2 (March - April 2006): 266, JSTOR.
 Helen A. Harrison, "Calder and Miro: Two Giants in Sync," The New York Times, June 21, 1998, LexisNexis Academic.