For the past three year, we have spent New Year's Eve at the Wealthy Theater in Grand Rapids listening to Michigan supergroup, Starlight Six. They usually play three sets of music, with short intermissions between sets. During one of the breaks last year, I was looking for something to do (trying to find a problem to play with) when I noticed the light string at the back of the stage.
The string of 25 lights were hung in a way that I could see two groups of 13.
This seemed quite appropriate given that it was 2013. And it got me wondering about what other groupings I might make with this string of lights.
I imagined using two interior anchor points (adding two more lights) in order to create three groups with nine in each group.
Making four groups meant adding three more lights. With 28 lights, each of these groups would have seven lights.
Five groups created a problem. When the four anchor lights, which were being double counted, were added to the original 25, I had a number that was not divisible by five. But six groups, with 25 (original) + 5 (anchor) lights, resulted in five lights per group. It had me wondering if other strings would be as "friendly" to various groupings or if there was something special about 25.
So I thought about a string of 26 lights. Two groups added one anchor resulting in 27 total, which is not divisible by two. Three groups added two anchors resulting in 28 total, which is not divisible by three. Four groups also didn't work. But five groups added four anchors for 30 total, and 30 is divisible by five - resulting in 6 bulbs per group.
This still left a lot of questions to explore. But the band was back on stage, so I filed this found problem away for another time.
Feel free to use it as a way to pass the time this coming year. Or better yet, find your own problem.