The most successful one was the first one, when 3 "stones" of 25 mm diameter came out and many many more smaller ones.
The big ones were conglomerates of smaller ones that were "glued together" by fresh light green "bilestone material". They had traces of the passage through the bowels, so the inner smaller stones showed their naked surface where the outer light green material was scrubbed away.
In the beginning I thought that the 25 mm Stones were expelled from the liver ducts directly.
Now, after further 22 flushes, i come to the firm conclusion that the soft light green sludge comes fresh from the liver in a soft liquid form or as small grains and gets shape and is being compressed while traveling through the intestine, capable of enclosing other stuff sometimes.
So, both is correct: the smaller (and often darker) "stones" are expelled from liver and gallbladder. And quite often they are wrapped by a layer of fresh soft sludge (of the lighter green color) which hardens on its way down- and outwards.