You start winding the lights around your tree... and realize you've got too many on the bottom, not enough on top...
It's a puzzle many of us have faced, but none of us has solved. Til now.
A math professor of the University of Mobile has done the math. And believe me, it's complicated.
But the good news is, he's got an online calculator, so you don't have to worry about sine or cosine or whatever else that was.
Just click HERE and plug in the required measurements, and you're good to go!