You've just met the three appeals — ethos, pathos and logos. Devices are the next layer down: the actual tools a speaker uses to deliver an appeal. And almost every one of them was born to solve one problem — how do you make a speech impossible to forget?
Picture a World with No Writing
For most of human history, a speech wasn't a document — it was a sound, made once, in a room, and gone. There was no script to hand out, no recording to replay. If your words were going to survive — get repeated at the well, passed on to the next town, remembered for years — they had to lodge in people's heads on the first hearing. So speakers leaned hard on the two things the ear loves best: repetition and rhythm.
That's the whole origin story. Anaphora (the same words at the start of line after line), the tricolon (things grouped in threes), plain repetition — these weren't invented to look clever on a page. They were invented because a line with a beat is a line you remember, and a line you remember is a line that works.
Why Threes, Why Repeats?
The rule of three (tricolon) feels complete in a way two or four never does — “life, liberty and the pursuit of happiness”, “blood, sweat and tears”. Your ear hears a beginning, a middle and a satisfying thud at the end. Anaphora — “We shall fight on the beaches, we shall fight on the landing grounds…” — builds a drumbeat that feels unstoppable, each repeat adding weight. And plain repetition drums one word home until it's all you can hear.
Flick the levers in the toy above. Notice the line never gets truer — it just gets harder to shake. That's the power, and it's two and a half thousand years old.