What a fascinating article! I was hoping it would address why we have certain word orders like black and white, macaroni and cheese, salt and pepper, peanut butter and jelly. Is there a rule for why we don't say white and black, cheese and macaroni, pepper and salt, jelly and peanut butter?  :)

There is something interesting going on with the sound that a clock with a pendulum makes.  In reality, the two different sounds that we describe as tick and tock in English are the exact same sound.  Your brain is organizing the sounds into groups of two.  If you try, you can change the tick sound to a tock sound.  Listen to the clock, and think this:  tick tock   tick tock   tick tock   tick tick tock   tick tock. 

That is great. Thank you for sharing it!