Lyric discussion by judomuerte 

Cover art for Bend to Squares lyrics by Death Cab for Cutie

The basis for this song relates to bending squares, or folding a paper. You can literally only fold a paper 7 times before it is no longer foldable. That machine can only bend to the square 5-6 times. Or, you can decide to be/do all these things, and never quite reach the end result of completely folding.

I think it is a reference to giving in to alcholism completely as evidenced by cutting the folds lengthwise, to completely throw away the efforts of bending to the squares completely. It's about giving up, whether with suicide or whatever, both images fit the progression of the lyrics.