Final answer:
Simplified shapes in the context of art are called geometric shapes, a concept particularly highlighted in Cubism through geometric abstraction and the transformation of subjects into geometric forms for a three-dimensional visual experience.
Step-by-step explanation:
Simplified shapes in art are commonly referred to as geometric shapes. This term describes shapes that are defined by precise lines and mathematical proportions, which are often found in geometric abstraction and movements such as Cubism. Cubism, in particular, showcases a distinctive approach where artists reconstruct subjects into geometric forms, creating a three-dimensional perspective on a two-dimensional plane. These forms can appear cube-like, meticulously arranged to alter the viewer's perception of space and form, as demonstrated in the works of Cubism artists like Picasso and Braque during the early 20th century. Over time, artists moved from Analytic Cubism, which overlaid surfaces in linear grids, to Synthetic Cubism, emphasizing flat, synthesized shapes in an abstract space.