A problem with this is that the river presumably goes all the way around the earth. Otherwise you could just travel west until you found its end. You really need a donut shaped earth, a sphere doesn’t help much
Surely it a river doesn’t go all the way around the earth. Rivers typically have one (or many) start points, where they are surrounded on three sides by land, meaning it’s possible to cross from one side to the other. Otherwise it’s just a strait or channel.
However, that assumes you are not on the land in between a fork in the river. In which case you would have to cross a bridge outside of Königsberg, and we might have to expand the problem to crossing every bridge on the continent once.
A problem with this is that the river presumably goes all the way around the earth. Otherwise you could just travel west until you found its end. You really need a donut shaped earth, a sphere doesn’t help much
Surely it a river doesn’t go all the way around the earth. Rivers typically have one (or many) start points, where they are surrounded on three sides by land, meaning it’s possible to cross from one side to the other. Otherwise it’s just a strait or channel.
However, that assumes you are not on the land in between a fork in the river. In which case you would have to cross a bridge outside of Königsberg, and we might have to expand the problem to crossing every bridge on the continent once.