A slender leaf
   floats downstream.

Its tip touches 
   a stouter leaf,
     sending the
     slender leaf 
     spinning.

The leaf continues to 
    twist as it drifts,

Making it seem spastic,
   but it neither rushes
     nor dawdles.

It matches the flow,
   letting gravity &
     currents do all the work.

It races only when it
    plunges through
     a narrow channel,

But it downshifts just as
      effortlessly as the
      stream widens.

The leaf's action is
   unforced, yielding to
     energy imparted upon it.