I
hope that by now you have discovered that this little piece of music is in the
exact form as the Bach puzzle canons we have just so intensively studied.
(Think
about the music again, if you have just discovered this.)
Therefore,
"Canon a 2" must mean that there are two voices which are in a
canonical relationship with each other. As the two visible voices are different,
there must be a third, missing voice! which is performed as a canon with one of
them.
But
which one?
As
the upper voice is more simple, could it be that the third voice is a
transformed version of that voice?
And
how is the missing voice to be performed?
Is
there a [start here symbol], or any clefs in weird positions to help us answer
this question?
No,
so we are on our own, as in the two "Seek and ye shall find" canons at
the end of the Musical Offering.
This,
then, is a real musical mystery to be solved!
For
those who really want a difficult musical challenge, try to solve the mystery
without any hints.