It is. and thats why that senna powder (1st ingredient in formula 2) is commonly avoided by people who believe thats why its actually has an anti-constipating effect on those who use it. to me, theres no way to explain why those crappy masses they're holding up would be anything other than intestinal layer.
By taking those pictures, they're attempting to make you believe that we have layers of old, thickened, muck and waste built up in our colons. This is simply just nonesense.
The only time "shit" builds up in your colon is when you're constipated, impacted, dehydrated, and so on. Kinda like John Wayne or Elvis. Otherwise, its totally clean. In case you're still a nonbeliever, find on the net a video of a colonoscopy.... usually clean as a whistle in there.