diff --git a/day_17/first.rb b/day_17/first.rb
new file mode 100644
index 0000000..f0fa5a3
--- /dev/null
+++ b/day_17/first.rb
@@ -0,0 +1,94 @@
+map = {}
+
+input = File.readlines('./input').map.with_index do |line, i|
+  line.chomp.chars.each_with_index { |char, pos| map[[pos, i, 0]] = char }
+end
+
+def draw_bounds(map)
+  x = map.keys.map { |x, _, _| x }
+  y = map.keys.map { |_, y, _| y }
+  z = map.keys.map { |_, _, z| z }
+
+  [x.min - 1, x.max + 1].each do |x|
+    (y.min - 1..y.max + 1).each do |y|
+      (z.min - 1..z.max + 1).each do |z|
+        map[[x, y, z]] = '.'
+      end
+    end
+  end
+
+  [y.min - 1, y.max + 1].each do |y|
+    (x.min - 1..x.max + 1).each do |x|
+      (z.min - 1..z.max + 1).each do |z|
+        map[[x, y, z]] = '.'
+      end
+    end
+  end
+
+  [z.min - 1, z.max + 1].each do |z|
+    (y.min - 1..y.max + 1).each do |y|
+      (x.min - 1..x.max + 1).each do |x|
+        map[[x, y, z]] = '.'
+      end
+    end
+  end
+
+  map
+end
+
+def surrounding_cords(cord)
+  x, y, z = cord
+  cords = [
+    # boottom
+    [x, y, z - 1],
+    [x - 1, y - 1, z - 1],
+    [x, y - 1, z - 1],
+    [x + 1, y - 1, z - 1],
+    [x - 1, y, z - 1],
+    [x + 1, y, z - 1],
+    [x - 1, y + 1, z - 1],
+    [x, y + 1, z - 1],
+    [x + 1, y + 1, z - 1],
+    # top
+    [x, y, z + 1],
+    [x - 1, y - 1, z + 1],
+    [x, y - 1, z + 1],
+    [x + 1, y - 1, z + 1],
+    [x - 1, y, z + 1],
+    [x + 1, y, z + 1],
+    [x - 1, y + 1, z + 1],
+    [x, y + 1, z + 1],
+    [x + 1, y + 1, z + 1],
+    # middle
+    [x - 1, y - 1, z],
+    [x, y - 1, z],
+    [x + 1, y - 1, z],
+    [x - 1, y, z],
+    [x + 1, y, z],
+    [x - 1, y + 1, z],
+    [x, y + 1, z],
+    [x + 1, y + 1, z]
+  ]
+end
+
+def cycle(map)
+  new_map = {}
+  map.each do |cord, _state|
+    neighbours_active = surrounding_cords(cord).map { |cord| map[cord] == '#' }.count(true)
+
+    if map[cord] == '#' && (2..3).include?(neighbours_active) ||
+       map[cord] == '.' && neighbours_active == 3
+      new_map[cord] = '#'; next
+    else
+      new_map[cord] = '.'
+    end
+  end
+  new_map
+end
+
+6.times do
+  map = draw_bounds(map)
+  map = cycle(map)
+end
+
+puts map.vales.count('#')
diff --git a/day_17/input b/day_17/input
new file mode 100644
index 0000000..c586985
--- /dev/null
+++ b/day_17/input
@@ -0,0 +1,8 @@
+.###.###
+.#.#...#
+..##.#..
+..##..##
+........
+##.#.#.#
+..###...
+.####...
diff --git a/day_17/second.rb b/day_17/second.rb
new file mode 100644
index 0000000..b1abed7
--- /dev/null
+++ b/day_17/second.rb
@@ -0,0 +1,172 @@
+map = {}
+
+input = File.readlines('./input').map.with_index do |line, i|
+  line.chomp.chars.each_with_index { |char, pos| map[[pos, i, 0, 0]] = char }
+end
+
+def draw_bounds(map)
+  x = map.keys.map { |x, _, _, _| x }
+  y = map.keys.map { |_, y, _, _| y }
+  z = map.keys.map { |_, _, z, _| z }
+  w = map.keys.map { |_, _, _, w| w }
+
+  [x.min - 1, x.max + 1].each do |x|
+    (y.min - 1..y.max + 1).each do |y|
+      (z.min - 1..z.max + 1).each do |z|
+        (w.min - 1..w.max + 1).each do |w|
+          map[[x, y, z, w]] = '.'
+        end
+      end
+    end
+  end
+
+  [y.min - 1, y.max + 1].each do |y|
+    (x.min - 1..x.max + 1).each do |x|
+      (z.min - 1..z.max + 1).each do |z|
+        (w.min - 1..w.max + 1).each do |w|
+          map[[x, y, z, w]] = '.'
+        end
+      end
+    end
+  end
+
+  [z.min - 1, z.max + 1].each do |z|
+    (y.min - 1..y.max + 1).each do |y|
+      (x.min - 1..x.max + 1).each do |x|
+        (w.min - 1..w.max + 1).each do |w|
+          map[[x, y, z, w]] = '.'
+        end
+      end
+    end
+  end
+
+  [w.min - 1, w.max + 1].each do |w|
+    (y.min - 1..y.max + 1).each do |y|
+      (x.min - 1..x.max + 1).each do |x|
+        (z.min - 1..z.max + 1).each do |z|
+          map[[x, y, z, w]] = '.'
+        end
+      end
+    end
+  end
+
+  map
+end
+
+def surrounding_cords(cord)
+  x, y, z, w = cord
+  cords = [
+    [x, y, z, w - 1],
+    [x, y, z, w + 1],
+
+    # boottom
+    [x, y, z - 1, w],
+    [x - 1, y - 1, z - 1, w],
+    [x, y - 1, z - 1, w],
+    [x + 1, y - 1, z - 1, w],
+    [x - 1, y, z - 1, w],
+    [x + 1, y, z - 1, w],
+    [x - 1, y + 1, z - 1, w],
+    [x, y + 1, z - 1, w],
+    [x + 1, y + 1, z - 1, w],
+    # top
+    [x, y, z + 1, w],
+    [x - 1, y - 1, z + 1, w],
+    [x, y - 1, z + 1, w],
+    [x + 1, y - 1, z + 1, w],
+    [x - 1, y, z + 1, w],
+    [x + 1, y, z + 1, w],
+    [x - 1, y + 1, z + 1, w],
+    [x, y + 1, z + 1, w],
+    [x + 1, y + 1, z + 1, w],
+    # middle
+    [x - 1, y - 1, z, w],
+    [x, y - 1, z, w],
+    [x + 1, y - 1, z, w],
+    [x - 1, y, z, w],
+    [x + 1, y, z, w],
+    [x - 1, y + 1, z, w],
+    [x, y + 1, z, w],
+    [x + 1, y + 1, z, w],
+
+    [x, y, z - 1, w - 1],
+    [x - 1, y - 1, z - 1, w - 1],
+    [x, y - 1, z - 1, w - 1],
+    [x + 1, y - 1, z - 1, w - 1],
+    [x - 1, y, z - 1, w - 1],
+    [x + 1, y, z - 1, w - 1],
+    [x - 1, y + 1, z - 1, w - 1],
+    [x, y + 1, z - 1, w - 1],
+    [x + 1, y + 1, z - 1, w - 1],
+    # top
+    [x, y, z + 1, w - 1],
+    [x - 1, y - 1, z + 1, w - 1],
+    [x, y - 1, z + 1, w - 1],
+    [x + 1, y - 1, z + 1, w - 1],
+    [x - 1, y, z + 1, w - 1],
+    [x + 1, y, z + 1, w - 1],
+    [x - 1, y + 1, z + 1, w - 1],
+    [x, y + 1, z + 1, w - 1],
+    [x + 1, y + 1, z + 1, w - 1],
+    # middle
+    [x - 1, y - 1, z, w - 1],
+    [x, y - 1, z, w - 1],
+    [x + 1, y - 1, z, w - 1],
+    [x - 1, y, z, w - 1],
+    [x + 1, y, z, w - 1],
+    [x - 1, y + 1, z, w - 1],
+    [x, y + 1, z, w - 1],
+    [x + 1, y + 1, z, w - 1],
+
+    [x, y, z - 1, w + 1],
+    [x - 1, y - 1, z - 1, w + 1],
+    [x, y - 1, z - 1, w + 1],
+    [x + 1, y - 1, z - 1, w + 1],
+    [x - 1, y, z - 1, w + 1],
+    [x + 1, y, z - 1, w + 1],
+    [x - 1, y + 1, z - 1, w + 1],
+    [x, y + 1, z - 1, w + 1],
+    [x + 1, y + 1, z - 1, w + 1],
+    # top
+    [x, y, z + 1, w + 1],
+    [x - 1, y - 1, z + 1, w + 1],
+    [x, y - 1, z + 1, w + 1],
+    [x + 1, y - 1, z + 1, w + 1],
+    [x - 1, y, z + 1, w + 1],
+    [x + 1, y, z + 1, w + 1],
+    [x - 1, y + 1, z + 1, w + 1],
+    [x, y + 1, z + 1, w + 1],
+    [x + 1, y + 1, z + 1, w + 1],
+    # middle
+    [x - 1, y - 1, z, w + 1],
+    [x, y - 1, z, w + 1],
+    [x + 1, y - 1, z, w + 1],
+    [x - 1, y, z, w + 1],
+    [x + 1, y, z, w + 1],
+    [x - 1, y + 1, z, w + 1],
+    [x, y + 1, z, w + 1],
+    [x + 1, y + 1, z, w + 1]
+  ]
+end
+
+def cycle(map)
+  new_map = {}
+  map.each do |cord, _state|
+    neighbours_active = surrounding_cords(cord).map { |cord| map[cord] == '#' }.count(true)
+
+    if map[cord] == '#' && (2..3).include?(neighbours_active) ||
+       map[cord] == '.' && neighbours_active == 3
+      new_map[cord] = '#'; next
+    else
+      new_map[cord] = '.'
+    end
+  end
+  new_map
+end
+
+6.times do
+  map = draw_bounds(map)
+  map = cycle(map)
+end
+
+puts map.values.count('#')
diff --git a/day_17/test b/day_17/test
new file mode 100644
index 0000000..eedd3d2
--- /dev/null
+++ b/day_17/test
@@ -0,0 +1,3 @@
+.#.
+..#
+###