十八世纪，俄国的哥尼斯堡有一条小河叫勒格尔河，河有两条支流，一条叫新河，一条叫旧河，它们在市中心汇合，在合流的地方中间有一座小岛，在小岛和两条支流上建有七座桥。哥尼斯堡的居民有个传统习惯，星期天沿着城市的河岸和小岛散步，同时试图找一条路线，可经过所有七桥 In the eighteenth century, there was a small river in Königsborg, Russia called the Legel River. There were two tributaries of the river, one called the New River and the other called the Old River. They converged in the city center and there was an island in the middle of the confluence. There are seven bridges on the island and two tributaries. Residents of Knysna have a traditional habit of walking along the city’s banks and islets on Sunday while trying to find a route that goes past all seven bridges