Modern production technology can complete commemorative coins with different shapes and complicated processes, such as diamound cut souvenir coins, Gear edges coins, Words stamped on side challenge coins and so on.
These processes can enhance the texture and collection price of commemorative coins.
In fact, the earliest proposed gear edges was the great scientist Newton. Before Newton was the director of the Royal Mint in his late years, the silver coins were round, and some people would secretly steal silver from the silver coins because these round silver coins were in circulation. after the friction will produce some deformation, the edge is not non-circular, even if some silver edges are scraped, the weight is lost, and the silver coins can be circulated normally.
In order to solve this problem, Newton proposed to change the round side of the silver coin to the gear side.
Later, people applied this shape to the commemorative coins. And created more patterns and practices.