It’s called the Bristol Stool Scale and it was medically designed to classify the form of different human feces! There are seven categories that each have a specific shape, color, and texture of feces to classify how healthy it is.
The scale was developed at the University of Bristol, hence the name, and was first published in 1997. The authors of the paper claim that by measuring your feces on this scale you can gain a sense of how healthy your colon is! Depending on how your feces compare will tell you what you need to change in your diet.
Feces types 1-3 indicate constipation, while 6 and 7 indicate diarrhea. Ideal feces should rank either a 4 or 5 on the scale. Think you’re healthy? See where you fall here.