diff --git a/d23.py b/d23.py
new file mode 100644
index 0000000..a7e68c4
--- /dev/null
+++ b/d23.py
@@ -0,0 +1,120 @@
+from lib import *
+
+EXAMPLE = """....#..
+..###.#
+#...#.#
+.#...##
+#.###..
+##.#.##
+.#..#..
+"""
+
+# EXAMPLE = """.....
+# ..##.
+# ..#..
+# .....
+# ..##.
+# .....
+# """
+
+N = (-1, 0)
+NE = (-1, 1)
+E = (0, 1)
+SE = (1, 1)
+S = (1, 0)
+SW = (1, -1)
+W = (0, -1)
+NW = (-1, -1)
+
+adj8 = [
+    N,
+    NE,
+    E,
+    SE,
+    S,
+    SW,
+    W,
+    NW,
+]
+
+def print_field(elves):
+    rmin, rmax = min(map(fst, elves)), max(map(fst, elves))
+    cmin, cmax = min(map(snd, elves)), max(map(snd, elves))
+    count = 0
+    for row in range(rmin, rmax + 1):
+        rs = ""
+        for col in range(cmin, cmax + 1):
+            if (row, col) in elves:
+                rs += "#"
+            else:
+                rs += "."
+                count += 1
+        print(rs)
+    print()
+    return count
+
+def solve(input: Input, second=False):
+    dirs_to_check = [
+        (N, NE, NW),
+        (S, SE, SW),
+        (W, NW, SW),
+        (E, NE, SE),
+    ]
+
+    round = 0
+    elves = input.grid2().find('#')
+    while True:
+        # print_field(elves)
+        nes = set()
+        proposed_fields = {}
+        for e in list(elves):
+            for o in adj8:
+                adj = (e[0] + o[0], e[1] + o[1])
+                if adj in elves:
+                    break
+            else:
+                nes.add(e)
+                continue
+
+            proposed_field = None
+            for dirs in dirs_to_check:
+                for o in dirs:
+                    adj = (e[0] + o[0], e[1] + o[1])
+                    if adj in elves:
+                        break
+                else:
+                    o = dirs[0]
+                    proposed_field = (e[0] + o[0], e[1] + o[1])
+                    break
+
+            if proposed_field is None:
+                nes.add(e)
+            elif proposed_field in proposed_fields:
+                proposed_fields[proposed_field].append(e)
+            else:
+                proposed_fields[proposed_field] = [e]
+
+        for ne, olves in proposed_fields.items():
+            if len(olves) == 1:
+                nes.add(ne)
+            else:
+                for e in olves:
+                    nes.add(e)
+
+        dirs_to_check = dirs_to_check[1:] + dirs_to_check[:1]
+        round += 1
+        if second and elves == nes:
+            return round
+        elif not second and  round == 10:
+            return print_field(nes)
+        elves = nes
+
+def main():
+    DAY_INPUT = "i23.txt"
+    print("Example  1:", solve(Input(EXAMPLE)))
+    print("Solution 1:", solve(Input(DAY_INPUT)))
+    print("Example  2:", solve(Input(EXAMPLE), True))
+    print("Solution 2:", solve(Input(DAY_INPUT), True))
+
+if __name__ == "__main__":
+    main()