  @even="#."*151
  ar=$stdin.read.split("\n")
  (ar.size-1).times do |n|
    h,w=ar[n].split.map(&:to_i)
    h.times do |i|
      print i.even? ? @even[0..w-1] : @even[1..w]
      print "\n"
    end
    print "\n"
  end
