Which design feature is described as having sturdy, straight lines and angular shapes?

The design feature characterized by sturdy, straight lines and angular shapes is known as "Yang." In the context of design, particularly when discussing principles of aesthetics and balance, Yang represents qualities that are strong, energetic, and typically associated with the masculine aspect of design. This concept is often contrasted with Yin, which embodies softer, rounder, and more gentle forms.

The usage of sturdy, straight lines and angular shapes in design can evoke feelings of stability, strength, and confidence. This aligns with the Yang principle, which emphasizes boldness and assertiveness in design elements. The other options, while they may contain certain elements of strength or structure, do not specifically embody the clear connotation of angular shapes and straight lines as effectively as Yang does. An hourglass shape is more flowing and curvy, the rectangle, while angular, lacks the energetic quality associated with Yang, and the inverted triangle often implies a dynamic tension rather than straightforward sturdiness.