A strategic puzzle centered around pouring liquids between containers of different capacities, with the goal of measuring exactly n liters.

Decanting problems (also known as jug-pouring problems or water-pouring problems) are where there are various containers with various known capacities for keeping various liquids.

The goal is to design a strategy for pouring the liquid between the bottles, so that a certain goal situation is reached.

A simple example is:

There are two bottles that can hold 3 litres and 5 litres respectively, and a bathtub with unlimited water.

How can 1 litre be measured?

Fill 3. Fill 5 with 3. Fill 3. Fill 5 with 3. 3 now has 1L.

More examples and analysis of the problems can be found here: