Create a collage that exemplifies the concept of 'aesthetic.' The collage could have elements such as finely coordinated colors, beautifully arranged shapes and patterns across the visuals. Include aesthetic components representing various thematic categories such as nature, architecture and abstract art. The nature theme could display a tranquil forest bathed in sunset hues, while the architecture portrays a sleek and modern building with pleasing lines. The abstract art should incorporate geometrical shapes with a harmonious color palette. Each element should evoke a sense of beauty, balance and visual harmony, encapsulating the essence of 'aesthetic.'