diff --git a/2016/ruby/day_08.rb b/2016/ruby/day_08.rb
new file mode 100644
index 0000000..3fbef3a
--- /dev/null
+++ b/2016/ruby/day_08.rb
@@ -0,0 +1,85 @@
+class Screen
+  attr_reader :width, :height, :pixels
+
+  def initialize(width, height)
+    @width, @height = width, height
+    @pixels = Array.new(height) { Array.new(width, false) }
+  end
+
+  def to_s
+    pixels.map {|row| row.map {|pixel| pixel ? ?# : ?. }.join }.join("\n")
+  end
+
+  def <<(instruction)
+    case instruction
+    when /rect (\d+)x(\d+)/
+      $1.to_i.times do |x|
+        $2.to_i.times do |y|
+          pixels[y][x] = true
+        end
+      end
+    when /rotate column x=(\d+) by (\d+)/
+      col = pixels.map {|row| row[$1.to_i] }.rotate(-$2.to_i)
+      pixels.each do |row|
+        row[$1.to_i] = col.shift
+      end
+    when /rotate row y=(\d+) by (\d+)/
+      row = pixels[$1.to_i].rotate(-$2.to_i)
+      pixels[$1.to_i] = row
+    end
+  end
+end
+
+if __FILE__ == $0
+  screen = Screen.new(50, 6)
+  DATA.lines.each do |line|
+    screen << line
+  end
+
+  puts screen
+  puts screen.pixels.map {|row| row.count {|pixel| pixel }}.inject(:+)
+end
+
+require 'minitest'
+# require 'minitest/autorun'
+
+class TestScreen < Minitest::Test
+  def test_screen
+    screen = Screen.new(7, 3)
+    assert_equal <<-PIXELS.chomp, screen.to_s
+.......
+.......
+.......
+    PIXELS
+
+    screen << 'rect 3x2'
+    assert_equal <<-PIXELS.chomp, screen.to_s
+###....
+###....
+.......
+    PIXELS
+
+    screen << 'rotate column x=1 by 1'
+    assert_equal <<-PIXELS.chomp, screen.to_s
+#.#....
+###....
+.#.....
+    PIXELS
+
+    screen << 'rotate row y=0 by 4'
+    assert_equal <<-PIXELS.chomp, screen.to_s
+....#.#
+###....
+.#.....
+    PIXELS
+
+    screen << 'rotate column x=1 by 1'
+    assert_equal <<-PIXELS.chomp, screen.to_s
+.#..#.#
+#.#....
+.#.....
+    PIXELS
+  end
+end
+
+__END__