diff --git a/17/17.2.py b/17/17.2.py
new file mode 100644
index 0000000..e131051
--- /dev/null
+++ b/17/17.2.py
@@ -0,0 +1,47 @@
+
+with open('input') as f:
+    data = f.read().strip().split('\n')
+
+initial = {(j, i, 0, 0) for i, s in enumerate(data) for j, c in enumerate(s) if c=='#'}
+
+def fence(s):
+    min_x = min(s, key=lambda x: x[0])[0]
+    min_y = min(s, key=lambda x: x[1])[1]
+    min_z = min(s, key=lambda x: x[2])[2]
+    min_w = min(s, key=lambda x: x[3])[3]
+    max_x = max(s, key=lambda x: x[0])[0]
+    max_y = max(s, key=lambda x: x[1])[1]
+    max_z = max(s, key=lambda x: x[2])[2]
+    max_w = max(s, key=lambda x: x[3])[3]
+    return (min_x-1, max_x+2), (min_y-1, max_y+2), (min_z-1, max_z+2), (min_w-1, max_w+2)
+
+def neighbours(s, x, y, z, w):
+    n=0
+    for _x in range(x-1, x+2):
+        for _y in range(y-1, y+2):
+            for _z in range(z-1, z+2):
+                for _w in range(w-1, w+2):
+                    if not (_x==x and _y==y and _z==z and _w==w):
+                        if (_x, _y, _z, _w) in s:
+                            n+=1
+    return n
+
+for _ in range(6):
+    new = set()
+    r_x, r_y, r_z, r_w = fence(initial)
+    for x in range(*r_x):
+        for y in range(*r_y):
+            for z in range(*r_z):
+                for w in range(*r_w):
+                    n = neighbours(initial, x, y, z, w)
+                    if (x,y,z, w) in initial:
+                        if n==2 or n==3:
+                            new.add((x,y,z,w))
+                    else:
+                        if n==3:
+                            new.add((x,y,z,w))
+    initial = new
+
+print(len(initial))
+                    
+print('done')
diff --git a/17/17.py b/17/17.py
new file mode 100644
index 0000000..bb25048
--- /dev/null
+++ b/17/17.py
@@ -0,0 +1,43 @@
+
+with open('input') as f:
+    data = f.read().strip().split('\n')
+
+initial = {(j, i, 0) for i, s in enumerate(data) for j, c in enumerate(s) if c=='#'}
+
+def fence(s):
+    min_x = min(s, key=lambda x: x[0])[0]
+    min_y = min(s, key=lambda x: x[1])[1]
+    min_z = min(s, key=lambda x: x[2])[2]
+    max_x = max(s, key=lambda x: x[0])[0]
+    max_y = max(s, key=lambda x: x[1])[1]
+    max_z = max(s, key=lambda x: x[2])[2]
+    return (min_x-1, max_x+2), (min_y-1, max_y+2), (min_z-1, max_z+2)
+
+def neighbours(s, x, y, z):
+    n=0
+    for _x in range(x-1, x+2):
+        for _y in range(y-1, y+2):
+            for _z in range(z-1, z+2):
+                if not (_x==x and _y==y and _z==z):
+                    if (_x, _y, _z) in s:
+                        n+=1
+    return n
+
+for _ in range(6):
+    new = set()
+    r_x, r_y, r_z = fence(initial)
+    for x in range(*r_x):
+        for y in range(*r_y):
+            for z in range(*r_z):
+                n = neighbours(initial, x, y, z)
+                if (x,y,z) in initial:
+                    if n==2 or n==3:
+                        new.add((x,y,z))
+                else:
+                    if n==3:
+                        new.add((x,y,z))
+    initial = new
+
+print(len(initial))
+                    
+print('done')
diff --git a/17/input b/17/input
new file mode 100644
index 0000000..7a77954
--- /dev/null
+++ b/17/input
@@ -0,0 +1,8 @@
+#.##....
+.#.#.##.
+###.....
+....##.#
+#....###
+.#.#.#..
+.##...##
+#..#.###