Final answer:
Mondrian believed that the universal elements of art were geometric shapes and primary colors, which reflected a universal order through harmony and balance in artworks such as 'Composition with Yellow, Blue and Red'. His work is influenced by Theosophy and seeks to express ideals beyond the physical world.
Step-by-step explanation:
Piet Mondrian, a prominent figure in the development of abstract art, believed art should mirror a universal order. Specifically, Mondrian thought that the universal elements of this order were represented by the use of geometric shapes and primary colors. He felt that these elements could reflect harmony and balance, embodying a sort of purity within the composition. His artworks, such as Composition with Yellow, Blue and Red (1937-42), exhibit the application of this philosophy, using straight vertical and horizontal lines to create distinct rectangles filled with primary colors to convey a sense of equilibrium and simplicity. Mondrian considered the application of these basic elements to be the means through which an artist could express a reality that goes beyond the physical world into the realm of the spiritual or the absolute. This approach is a reflection of Mondrian's engagement with Theosophy, which influenced many artists in the early European Avant-garde.