Here is Science without mathematics. [thought experiment I'm
   making up right now]:

   "Yesterday, I launched a balloon into the sky. The shadow on the
   ground had reached the bench in my backyard.

   When the shadow reached the other side of the bench, I received
   a phone call from my neighbor. He received the balloon.

   I repeated this experiment when the shadow reached the bench in
   my backyard again.

   Now, I received a call from a different neighbor when the shadow
   reached the barn.

   This neighbor was not on the same road as I, but a different
   road entirely.

   I conclude that the wind does not always travel down the road to
   the same neighbor whenever I launch a balloon when the shadow
   reaches my bench.