system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why aren't guitar frets evenly spaced?
gpt
Because for a string instrument, notes have a multiplicative, not an additive relationship. For example lets take a string that's tuned to an E. In order to play an E one octave higher you have to place your finger in the middle of the string, effectively cutting its length in half. To go up to the next E, you put your finger at the middle point between the last octave and the end of the string, making it effectively one quarter of the length of the full string. So, if you were to put frets to mark three octaves, it would look something like this

--------|----|--|--

As you can see, they get progressively closer, just like the frets of a guitar. The difference there is that the guitar frets don't just mark octaves but the other notes in between.