In the Tetris domain visualization, each object on the grid represents a Tetris piece or an empty grid cell. The diagram uses different shapes, colors, and text labels to convey the type, position, and status of each object.

- **Shapes**: 
  - A single square represents a one-square piece. 
  - A two-square straight piece would be represented by two connected squares.
  - An "L" shaped piece is represented by three connected squares forming an "L" shape. 
  - Grid cells are represented as individual squares.

- **Colors**:
  - Each type of Tetris piece is assigned a unique color to differentiate it from others. For instance, a single-square piece might be red, a two-square piece could be yellow, and an "L" shaped piece might be blue or green.
  - Grid cells are typically uncolored or have a neutral color to indicate they are empty.

- **Bold Edges**:
  - The outer edges of each Tetris piece are bolded to distinguish the piece from the grid and other pieces. Inner edges within the piece are not bolded to maintain clarity.

- **Text Labels**:
  - Each piece has a text identifier placed slightly higher within its shape to avoid overlap with other text.
  - Grid cells have their position identifiers centered within the square.

- **Status Indicators**:
  - The status of each object is indicated by the color of the object. For example, red might indicate "occupied," while green might indicate "clear."
  - Textual status is included within the shape, using short phrases like "occ" for occupied and "clr" for clear.

- **Legend**:
  - A legend is included to map colors to their respective statuses and object types, ensuring that viewers can easily interpret the diagram.

- **Contrast and Readability**:
  - Text is placed to ensure high contrast with the background, enhancing readability. This might involve choosing contrasting colors for text and background or adjusting the position of text to avoid overlap.

- **Relative Locations and Sizes**:
  - The grid is organized in a structured manner, with rows and columns clearly defined. Each object is placed according to its specified position, ensuring no overlap.
  - The size of each shape corresponds to the size of the piece it represents, with single squares for one-square pieces and larger configurations for multi-square pieces.

This encoding ensures that the diagram is informative, clear, and easy to understand for anyone viewing it, regardless of their familiarity with the Tetris domain.