(a) Is it possible to color red some of the unit squares of a 2009x2009 grid
so that every non-red unit square shares a side with exactly one red square,
without two red unit squares share any sides?
(b) Is it possible to color red some of the unit squares of a 2009x2009 grid
so that every unit square, even the red ones, shares a side with exactly one red square,
(c) Is it possible to color red some of the unit squares of a 2009x2009 grid
so that every non-red unit square shares a side with exactly one red square,
but two red unit squares can share any sides?