Keep in mind that a selector only keeps the previous input arguments in its cache. If you reuse this selector with another multiply factor, the selector would always have to re-evaluate its value. This is because it's receiving both of the multiply factors (e.g. one time 2, the other time 4). In order to correctly memoize the selector, wrap the selector inside a factory function to create different instances of the selector.

The following is an example of using multiple counters differentiated by id.