In the Tetris domain visualization, each object is represented as follows:

1. **Shapes and Sizes**:
   - **One-square piece**: Represented by a single square. This shape indicates that the piece occupies only one grid position.
   - **Two-square straight piece**: Represented by two connected squares in a straight line. This indicates that the piece occupies two adjacent grid positions.
   - **Right-L piece**: Represented by three connected squares forming an "L" shape. This indicates that the piece occupies three grid positions in an "L" configuration.
   - **Grid Cells**: Represented by individual squares, indicating the positions on the grid that can be occupied by pieces.

2. **Colors**:
   - Each type of Tetris piece is assigned a unique color to distinguish it from others. For instance, blue, green, red, and yellow can be used to represent different pieces.
   - Clear grid cells are typically left without color to indicate their availability for occupation by a piece.
   - The colors are chosen to ensure high contrast with text for readability.

3. **Text Labels and Status**:
   - Each piece and grid cell is labeled with its identifier (e.g., "rightl0", "square1") to indicate which piece it is.
   - The status of each grid cell is labeled as "occupied" or "clear" to indicate whether it is currently occupied by a piece or available.
   - Text is strategically placed within each shape to avoid overlap and ensure readability.

4. **Bold Edges**:
   - The outer edges of each piece are bolded to differentiate the piece from the grid and highlight its boundaries. This is especially useful for complex shapes like the "L" piece.

5. **Legend**:
   - A legend is included to map colors to the status of grid cells and pieces. For example, a specific color could indicate that a cell is "occupied" while another indicates "clear".
   - The legend is positioned outside the main grid area to avoid overlap with the diagram.

Overall, the visualization aims to clearly represent the layout and status of each piece and grid cell, making it easy to understand the current state of the Tetris grid.