When we remodeled our home, we decided to install a dual toilet-tissue holder...
We discovered that although we now had two rolls instead of one, the problem was not solved. Both rolls ran out at the same time... We had discovered that the switch to two rolls meant we had to use more sophisticated behavior: the algorithm for tearing of paper mattered.
After some self-observation and discussion, we discovered that three different algorithms were in use: large, small, and random.
* Algorithm Large: Always take paper from the largest roll.
* Algorithm Small: Always take paper from the smallest roll.
* Algorithm Random: Don't think -- select the roll randomly
We had assumed that Algorithm Random was most natural. After all, we had bought the dual-roll holder specifically so that we wouldn't have to think. But were our selections truly random, we would chose each roll roughly equally, so they would both empty at the same time -- or close. Algorithm random is not the one to use. To use toilet paper requires thought...