diff --git a/11/code.js b/11/code.js
new file mode 100644
index 0000000..f2dd2f9
--- /dev/null
+++ b/11/code.js
@@ -0,0 +1,72 @@
+const fs = require('fs');
+const inputArray = fs.readFileSync('input.txt').toString().split("\n");
+
+const octopi = [];
+for (const line of inputArray) {
+  octopi.push(line.split("").map(Number));
+}
+
+const height = octopi.length;
+const width = octopi[0].length;
+
+// Part One
+// const runs = 100;
+
+// Part Two
+const runs = 1000;
+
+let flashes = 0;
+
+function flash(flashed) {
+  let flashing = 0;
+  for (let h = 0; h < height; h++) {
+    for (let w = 0; w < width; w++) {
+      const coords = `${h}-${w}`;
+      if (!flashed.includes(coords) && octopi[h][w] > 9) {
+        flashes++;
+        flashing++;
+        flashed.push(coords);
+        if (h >= 1) {
+          if (w >= 1) octopi[h-1][w-1]++;
+          octopi[h-1][w]++;
+          if (w < width - 1) octopi[h-1][w+1]++;
+        }
+        if (w >= 1) octopi[h][w-1]++;
+        if (w < width - 1) octopi[h][w+1]++;
+        if (h < height - 1) {
+          if (w >= 1) octopi[h+1][w-1]++;
+          octopi[h+1][w]++;
+          if (w < width - 1) octopi[h+1][w+1]++;
+        }
+
+      }
+    }
+  }
+  if (flashing === 0) return;
+  flash(flashed);
+  return;
+}
+
+for (let r = 1; r <= runs; r++) {
+  const flashed = [];
+  for (let h = 0; h < height; h++) {
+    for (let w = 0; w < width; w++) {
+      octopi[h][w]++;
+    }
+  }
+  flash(flashed);
+  for (let h = 0; h < height; h++) {
+    for (let w = 0; w < width; w++) {
+      if (octopi[h][w] > 9) {
+        octopi[h][w] = 0;
+      }
+    }
+  }
+
+  if (octopi.flat().reduce((a, b) => parseInt(a) + parseInt(b), 0) === 0) {
+    console.log(`Synchronized on run ${r}`);
+    break;
+  }
+}
+
+console.log(`Total flashes: ${flashes}`);
\ No newline at end of file
diff --git a/11/input.txt b/11/input.txt
new file mode 100644
index 0000000..07c27d2
--- /dev/null
+++ b/11/input.txt
@@ -0,0 +1,10 @@
+4743378318
+4664212844
+2535667884
+3273363861
+2282432612
+2166612134
+3776334513
+8123852583
+8181786685
+4362533174
\ No newline at end of file
diff --git a/11/sample.txt b/11/sample.txt
new file mode 100644
index 0000000..a3819c9
--- /dev/null
+++ b/11/sample.txt
@@ -0,0 +1,10 @@
+5483143223
+2745854711
+5264556173
+6141336146
+6357385478
+4167524645
+2176841721
+6882881134
+4846848554
+5283751526
\ No newline at end of file