h, w = read_line.split.map(&.to_i)
k = read_line.to_i64
k %= (h * w * 4)
y = 0
x = 0
dy = 1
dx = 1
ans = Array.new(h) { Array.new(w, false) }
k.times do
  ans[y][x] = !ans[y][x]
  if y + dy < 0 || h <= y + dy
    dy *= -1
  else
    y += dy
  end
  if x + dx < 0 || w <= x + dx
    dx *= -1
  else
    x += dx
  end
end
h.times do |i|
  puts w.times.map { |j| ans[i][j] ? '#' : '.' }.join
end

def move(l, k)
  ret = Array.new(l, false)
  len = k % (l * 2)
  if len < k
    len.times { |i| ret[i] = true }
  else
    ret.fill(true)
    (len - k).times { |i| ret[l - 1 - i] = false }
  end
  return ret
end