"he pours the potions on the floor." is an example of
rhythm
meter
assonance
alliteration

This is an example of alliteration. The words "pours" and "potions" being near each other create that rhythmic feeling when you say the phrase aloud. 

An alliteration is a poetic device that creates a sort of rhythm by using several words in a phrase that each start with the same sound. "Peter Piper picked a peck of pickled peppers" is another common example of an alliteration.

Because writing on paper is said to engrave what your writing down into your brain therefore writing your thoughts is better than speaking them.