It's all there in the first seven minutes of Donald in Mathmagic Land, a 27-minute film released June 26, 1959. According to Wikipedia, "The film was made available to schools and became one of the most popular educational films ever made by Disney" (https://en.wikipedia.org/wiki/Donald_in_Mathmagic_Land). It transports Donald Duck back to ancient Greece, explains Pythagoras' contribution to math and even features Donald jamming with ancient Greek cartoon musicians, as shown above.
You can watch it on YouTube by clicking here:
I wish they'd had it out when I was struggling with math in elementary school!
Hat tip, BTW, to Göran Carlström of the Nordiska Psalmodikonförbundet in Sweden for getting me off on this tangent by referring to the psalmodikon as the "oldest musical instrument" on Facebook. The psalmodikon, a one-stringed Swedish box zither, is a type of monochord -- and Pythagoras is credited with inventing the monochord. From FB, I Googled the monochord and found a reference to the Disney film.
The rest, as they say, is history. Or math.