Harmonic Motion

A rhythm poem

Back and forth and back and forth
the oscillations glide
up and down and up and down
the regulated motion
round and round and round and round
they return to where they had begun
back and forth and back and forth
a stable equilibrium
up and down and up and down
that displaced is that returned
round and round and round and round
the force is negative kx
back and forth and back and forth
keep even frequency
round and round and round and round
which angularly found is 2 over T
back and forth and back and forth
unless there's some nonzero b
up and down and up and down
which disrupts the even patterns,
round and round and round and round
for not all periodic motion is
simple.