Sure, here's an example of how LED letters could be designed:

```
+-------------------+
|                   |
|   ┌───────────┐   |
|   │           │   |
|   │    L E D  │   |
|   │           │   |
|   └───────────┘   |
|                   |
|   ┌───────────┐   |
|   │           │   |
|   │  L E T T E│   |
|   │           │   |
|   └───────────┘   |
|                   |
|   ┌───────────┐   |
|   │           │   |
|   │    E R S  │   |
|   │           │   |
|   └───────────┘   |
|                   |
+-------------------+
```

This design features individual LED letter modules that can be arranged to spell out words or phrases. Some key elements:

Each letter is contained within a rectangular module with a recessed area for the LED lights.
The modules have a sleek, minimalist aesthetic with clean lines and a metallic or glossy finish.
The LED lights within each module can be programmed to illuminate in various colors, patterns, and animations.
The modular design allows for flexibility in arranging the letters to fit different sizes and layouts.

Additional design considerations for LED letters:

Choosing optimal LED brightness and diffusion to ensure clear visibility
incorporating heat dissipation elements to prevent overheating
Designing intuitive controls and programming interfaces
seamless integration with any surrounding architecture or branding

This is just one example of how LED letters could be visually represented. The specific design can be further customized with different fonts, layouts, color schemes, and interactive features to suit the needs of a particular application, such as indoor or outdoor signage, event displays, or architectural elements.