i’m actually kind of reluctant to post this;
it’s probably the best idea i’ve had since
i started making up lectures without words
and now it’ll be easy to steal. you saw it
here first.
the Big triangle is made up of seven Little triangles.
each Little has seven Points. moreover the Points
of each Little (considered as subobjects of their Little)
are arranged in the same pattern
as the Littles themselves are (considered
as subobjects of Big).
pick any Little and call it L1.
there are three dark points in L1.
find the three Littles that correspond
to these three Points.
(for example, let L1 be the lower-left Little;
the three Littles i refer to now run along
the right side of Big [just as the dark Points
run along the right side of L1]).
the three Littles in question are then
precisely those in which the Point…
P1, say… that corresponds to L1
(considered as a subobject of Big)
is dark. i’ll be here all week.
(it’s better with the handwaving.)
and 
;
is left as an exercise).
