gistfile1.rb

color = 0
j = 1
Sites.all.each do |site|
   2.times do
   i = 0
   post = site.posts.reverse[i]
   if nada
      blanco
   elsif color.modulo(2) == 0
      rojo
   else verde
   end
   j += 1
   if j == 2
     color += 1
     j = 0
   end
   i += 1
end