Formation:

One child is selected to be the witch. He or she marks out circles in a certain territory. These become her 'jars.' When anyone ventures near her territory, she tries to catch them and put them in one of the 'jars'.

As the witch walks about their territory, he or she chants:

If she captures one person, that person can be rescued by any child who can get to the 'jar' without being touched by the witch. But if she manages to get two of them in the same jar, they are glued in place and can't be rescued.

The game can last as long as you want -- until the first pair is glued in place (at which point you can simply start over again), or until there's nobody left to rescue a child. (Or until they're just too darned tired to run anymore.) :-)