Jim Kelley wrote:
When you think of interference as being the instantaneous sum of waves
at a given position and time, then there is really only one kind of
interference to be had - though there are a variety of results which can
be obtained from it.

If, as you say, interference is only a result and
not a cause, how can there possibly be "a variety
of results which can be obtained from (interference)"?
--
73, Cecil http://www.w5dxp.com