most home toilets have a single holder for a single roll. when the roll empties, then what? we discovered that although we now had two rolls instead of one, the problem was not solved. after some self-observation and discussion, we discovered that three different algorithms were in use: large, small, and random. large: always take paper from the largest roll. small: always take paper from the smallest roll. random: don’t think — select the roll randomly toilet paper algorithms via kottke