1. **Safe Materials**  
   Use non-toxic, eco-friendly wood or food-grade plastic to avoid harmful chemicals.

2. **Proper Size**  
   The seesaw and swing should be sized appropriately for the hamster’s body to ensure comfortable movement.

3. **Stable Structure**  
   The base should be heavy or wide enough to prevent tipping, and joints should be sturdy.

4. **Combined Functions**  
   One end of the seesaw can be made into a swing seat, or the seesaw and swing can be designed separately to increase fun.

5. **Easy to Clean**  
   The toy’s surface should be smooth and easy to clean to prevent bacteria growth.

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### Simple Design 

- **Base**: Rectangular wooden board with non-slip surface.  
- **Seesaw**: A long wooden plank with a bearing in the middle, allowing it to pivot up and down.  
- **Swing**: A small wooden seat hung by thin ropes from a wooden rod fixed above the base.