Which hairstyle trend was popularized by Vidal Sassoon in the 1960s?

Vidal Sassoon revolutionized the world of hairstyling in the 1960s with his innovative approach to cutting hair, particularly through the introduction of geometric cuts. These styles were characterized by their precise, clean lines and structured shapes that emphasized form and movement. Sassoon's techniques focused on creating hairstyles that were not only visually striking but also easier to manage and maintain. The geometric cuts he popularized were avant-garde for their time, moving away from traditional styling methods and embracing a more modern, architectural approach.

This trend aligned with the broader cultural shifts of the 1960s, reflecting a desire for individuality and self-expression through bold hairstyles. The simplicity and elegance of Sassoon's geometric cuts also complemented the fashion of the era, making them highly sought after. In contrast, the other hairstyle options listed, such as hippie waves, afros, and shag cuts, while significant in their own right, did not stem from Sassoon's innovations during that pivotal decade.