diff --git a/progress.png b/progress.png
index 21aa751..383a139 100644
Binary files a/progress.png and b/progress.png differ
diff --git a/progress.yaml b/progress.yaml
index 80bd6a7..0fd1852 100644
--- a/progress.yaml
+++ b/progress.yaml
@@ -3,4 +3,6 @@
 2:
   stars: 2
 3:
-  stars: 2
\ No newline at end of file
+  stars: 2
+4:
+  stars: 1
\ No newline at end of file
diff --git a/res/examples/day4.txt b/res/examples/day4.txt
new file mode 100644
index 0000000..c41c5ea
--- /dev/null
+++ b/res/examples/day4.txt
@@ -0,0 +1,10 @@
+MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX
\ No newline at end of file
diff --git a/src/day4/puzzle1.typ b/src/day4/puzzle1.typ
new file mode 100644
index 0000000..d4a44ee
--- /dev/null
+++ b/src/day4/puzzle1.typ
@@ -0,0 +1,57 @@
+#import "/src/utils.typ": *
+
+#let check-xmas(lines, ox, oy) = {
+  let w = lines.first().len()
+  let h = lines.len()
+
+  let total = 0
+  for dy in (-1, 0, 1) {
+    for dx in (-1, 0, 1) {
+      if dx == 0 and dy == 0 {
+        continue
+      }
+      let buffer = ""
+      let x = ox
+      let y = oy
+      for i in range(4) {
+        buffer += lines.at(y).at(x)
+        x += dx
+        y += dy
+        if (
+          not "XMAS".starts-with(buffer) or
+          x < 0 or x >= w or
+          y < 0 or y >= h
+        ) {
+          break
+        }
+      }
+      if buffer == "XMAS" {
+        total += 1
+      }
+    }
+  }
+  return total
+}
+
+#let solve(input) = {
+  let lines = input.split("\n")
+  let w = lines.first().len()
+  let h = lines.len()
+
+  let total = 0
+  for y in range(h) {
+    for x in range(h) {
+      if lines.at(y).at(x) == "X" {
+        total += check-xmas(lines, x, y)
+      }
+    }
+  }
+
+  return total
+}
+
+#show-puzzle(
+  4, 1,
+  solve,
+  example: 18
+)
\ No newline at end of file
diff --git a/src/day4/puzzle2.typ b/src/day4/puzzle2.typ
new file mode 100644
index 0000000..e69de29
diff --git a/src/main.pdf b/src/main.pdf
index d93f21f..41d6b48 100644
Binary files a/src/main.pdf and b/src/main.pdf differ