Paolo, Van, and Carlos are fishermen who live next to a lake that is open to fishing; in other words, anyone is free to use the lake for fishing. Assume that these men are the only three fishermen who fish in this lake and that the lake is large enough for all three fishermen to fish intensively at the same time.
Each year, the fishermen choose independently how many fish to catch; specifically, they choose whether to fish intensively (that is, to place several fishing lines in the water for long periods of time, which hurts the sustainability of the lake if enough people do it) or to fish nonintensively (which does not hurt the sustainability of the lake). None of them has the ability to control how much the others fish, and each fisherman cares only about his own profitability and not about the state of the lake.
Assume that as long as no more than one fisherman fishes intensively, there are enough fish to restock the lake. However, if two or more fish intensively, the lake will become useless in the future. Of course, fishing intensively earns a fisherman more money and greater profit because he can sell more fish.
The lake is an example of (a private good, a public good, a club good, a common resource) because the fish in the lake are (non excludable, excludable) and (rival in consumption, nonrival in consumption)