The basic principle is simple - light shines backward instead of forward. Each letter consists of an aluminum shell with a solid face (usually acrylic or metal). LED strips mount inside, positioned to direct light toward the wall rather than through the face.

When powered on, light bounces off the mounting surface and creates a glow around each letter's perimeter. The effect is sometimes called a "halo" because the letter appears outlined in light against the wall.

This approach requires proper wall surfaces. Light-colored, smooth walls work best. Dark walls absorb too much light, reducing visibility. Textured or uneven surfaces create irregular halos that look amateurish. Some installations include separate backer panels - painted boards mounted behind letters to provide consistent light-colored surfaces regardless of the actual wall color.