Create a simplified diagram illustrating vehicle drivetrain layouts with four configurations: Rear-Wheel Drive (RWD), Front-Wheel Drive (FWD), All-Wheel Drive (AWD), and Four-Wheel Drive (4x4). 

1. **Design Features**: 
   - Use abstract shapes instead of detailed engine and wheel designs.
   - Change tire color to blue and modify the axle layout for a more stylized appearance.
   - Use geometric icons to represent drivetrain components instead of realistic images.

2. **Text Labels**: 
   - Replace the current text labels with symbols or simplified titles, such as “R”, “F”, “A”, and “X” to denote each configuration.

3. **Background**: 
   - Use a contrasting color background, like light gray, to enhance the visibility of the diagram. 

4. **Overall Layout**: 
   - Arrange the configurations in a linear format, ensuring equal spacing between each layout for clarity.

Make it clear, visually appealing, and easy to understand while removing any brand-specific references.