A skunk sat on a stump
and thunk the stump stunk,
but the stump thunk
the skunk
stunk.
Traditional tongue twister e.g. http://tongue-twisters-database.blogspot.com/2009/04/skunk-sat-on-stump-and-thunk-stump.html
A TRU Writer powered SPLOT: Philosophy of Emotions (F19)