diff --git a/2024/day06.py b/2024/day06.py
new file mode 100644
index 0000000..e281ab2
--- /dev/null
+++ b/2024/day06.py
@@ -0,0 +1,59 @@
+import fileinput
+from utils import Point, N, S, E, W
+
+
+DIRS = [S, E, N, W]
+
+def simulate(board, start, obs=None):
+    BOARD[obs] = '#'
+    p = start
+    d = 0
+    seen = set()
+
+    while True:
+        if (p, d) in seen:
+            # Loop detected.
+            BOARD[obs] = '.'
+            return None
+
+        seen.add((p, d))
+
+        np = p + DIRS[d]
+        if BOARD.get(np) == '#':
+            d = (d + 1) % 4
+        elif BOARD.get(np) is None:
+            break
+        else:
+            p += DIRS[d]
+
+    BOARD[obs] = '.'
+    return set(p for p, _ in seen)
+
+# Read problem input.
+BOARD = {}
+for y, line in enumerate(fileinput.input()):
+    for x, c in enumerate(line.strip()):
+        p = Point(x, y)
+        BOARD[p] = c
+        if c == '^':
+            START = p
+
+# Solve part 1.
+seen = simulate(BOARD, START)
+print("Part 1:", len(seen))
+
+# Solve part 2.
+candidates = set()
+for x in seen:
+    for n in x.neighbours():
+        candidates.add(n)
+
+part_2 = 0
+for p in candidates:
+    if p not in seen or BOARD.get(p) != '.':
+        continue
+    if simulate(BOARD, START, obs=p) is None:
+        part_2 += 1
+
+print("Part 2:", part_2)
+