In the Tetris domain visualization, each object is represented using geometric shapes, colors, and text labels to convey its identity, status, and position within the grid. Here's a breakdown of the visual encoding:

1. **Shapes and Sizes:**
   - **One-square Piece:** Represented by a single square. This indicates it occupies a single grid position.
   - **Two-square Straight Piece:** Not applicable in the initial state but would be represented by two connected squares in a straight line.
   - **Right-L Piece:** Represented by an "L" shape composed of three connected squares. This shape indicates the unique configuration of the piece within the grid.

2. **Colors:**
   - Each piece type is assigned a distinct color to differentiate between them visually:
     - **Blue:** Represents the "rightl0" L-shaped piece.
     - **Green:** Represents the "rightl1" L-shaped piece.
     - **Red:** Represents the "square0" one-square piece.
     - **Yellow:** Represents the "square1" one-square piece.
   - **White:** Used for unoccupied (clear) grid cells, indicating they are available for movement or rotation of pieces.

3. **Text Labels:**
   - Each piece has a text identifier (e.g., "rightl0", "square0") positioned slightly higher within its shape to avoid overlap with other text.
   - The status of each grid cell is labeled as "occupied" or "clear," with "occupied" cells having a color corresponding to the piece occupying them.

4. **Outer Edges:**
   - The outer edges of each piece are bolded to distinguish them from the grid lines, emphasizing the boundaries of the pieces.

5. **Legend:**
   - A legend is included to map colors to their respective statuses, ensuring clarity for viewers. It provides a quick reference to understand the meaning of each color used in the diagram.

6. **Layout and Positioning:**
   - The grid is organized in a 6-row by 4-column layout, with positions labeled to indicate their row and column indices (e.g., "f5-0f").
   - Text is positioned to maximize readability and avoid overlap, ensuring all labels and status indicators are clearly visible.

This encoding ensures that the diagram effectively communicates the initial state of the Tetris puzzle, allowing viewers to understand the configuration and status of each piece and grid cell.