When 2 or more people are taking a dump in a public restroom... The resulting combined odor, when detected by the olfactory glands of anyone present causes them to see a "brown flash".... Similar to a nuclear criticality ....both are caused by a critical mass of "PU".
Pete is no longer allowed to poop in our restroom when someone else is already in there...he has caused too many people to experience a shiticality induced brown flash due to his high fecal enrichment.
A public restroom that possesses combined levels of cleanliness, comfort, amenities and also provides both visual and olfactory appeal which can be rated and/or ranked on a scale of 1 to 10, (10 being the best, fractional numeric values can be utilized, i.e. 6.7, or 9.2, etc.) by the individual having to sit down on a toilet to urinate (piss) and/or for a bowel movement (shat).
The shatability of the crapper in that resturant was a solid 8. The owner of this establishment would be well served to improve the shatability rating to at least a 6.5 to ensure repeat customers. Only a shatability scale that allows a less then zero rating could best describe that restroom.