Final answer:
Geometric and organic shapes became popular in art and design, breaking away from the traditional square and rectangle shapes.
Step-by-step explanation:
The shapes that started to become more popular than the previous square and rectangle were geometric and organic shapes.
Geometric shapes, such as rectangles, triangles, and circles, began to be used in various art forms and designs. Artists like Piet Mondrian and Eero Saarinen used geometric shapes extensively in their works. Organic shapes, on the other hand, are shapes that resemble natural forms, like the curvilinear forms seen in Egyptian and Muslim art.
These new shapes added more variety and visual interest to artworks and designs, breaking away from the traditional square and rectangle shapes.