What are the requirements for glass marbles used in checkers
Glass marbles for checkers need to meet the following requirements: 1. Consistent diameter: The diameter of glass marbles needs to be consistent to ensure that there will be no deviation when moving on the checkers board and maintain a smooth movement. 2. Smooth surface: The surface of the glass marble needs to be smooth to ensure smooth sliding on the checkers board. 3. Moderate hardness: Glass marbles should not be too hard or too soft. Moderate hardness can ensure that the marbles are not easy to break when they fall to the ground. 4. Not easy to break: Glass marbles should not be fragile to ensure that they are not easy to break and affect the game effect during the game. 5. The color should be clear and bright: The color of the glass marbles needs to be clear and bright, which is easy to identify and makes the game more interesting.