Some resources which already exist on the map (fruit and fish) will recover resources over time when they are not being gathered. The rate of regeneration needs to be decided. 1. Constant regeneration. This is very simple, the amount of resources increases by the same amount each second. 2. Sigmoid regeneration. This varies the regeneration rate based on the current resources. When the resource is close to empty then the rate is slow and when the resource is nearly full the rate is also slow.