diff --git a/solutions/day11/solution.js b/solutions/day11/solution.js
index 61e79c7..9f2dddc 100644
--- a/solutions/day11/solution.js
+++ b/solutions/day11/solution.js
@@ -11,11 +11,11 @@ async function run () {
   await solveForSecondStar(input)
 }
 
-function draw (input) {
-  for (const row of input) {
-    console.log(row.join(''))
-  }
-}
+// function draw (input) {
+//   for (const row of input) {
+//     console.log(row.join(''))
+//   }
+// }
 
 function neighbors (input, row, col) {
   let total = 0
@@ -48,20 +48,19 @@ function step (input) {
 function stabilize (input) {
   // console.log('\nInput\n--------')
   // draw(input)
-  let rounds = 1; let old; let fresh = input
+  let old; let fresh = input
   do {
     old = fresh
     fresh = step(old)
     // console.log(`\nRound ${rounds}\n--------`)
     // draw(fresh)
-    rounds++
   } while (JSON.stringify(old) !== JSON.stringify(fresh))
   return fresh
 }
 
 async function solveForFirstStar (input) {
   const stable = stabilize(input)
-  const filledSeats = stable.flat(2).filter(x => x == '#').length
+  const filledSeats = stable.flat(2).filter(x => x === '#').length
   report('Solution 1:', filledSeats)
 }
 
diff --git a/solutions/day15/input.txt b/solutions/day15/input.txt
new file mode 100644
index 0000000..0c5df98
--- /dev/null
+++ b/solutions/day15/input.txt
@@ -0,0 +1 @@
+9,12,1,4,17,0,18
\ No newline at end of file
diff --git a/solutions/day15/solution.js b/solutions/day15/solution.js
new file mode 100644
index 0000000..630c5c9
--- /dev/null
+++ b/solutions/day15/solution.js
@@ -0,0 +1,44 @@
+const path = require('path')
+const { read, position } = require('promise-path')
+const fromHere = position(__dirname)
+const report = (...messages) => console.log(`[${require(fromHere('../../package.json')).logName} / ${__dirname.split(path.sep).pop()}]`, ...messages)
+
+async function run () {
+  const input = (await read(fromHere('input.txt'), 'utf8')).trim().split(',').map(x => 1 * x)
+
+  await solveForFirstStar(input)
+  await solveForSecondStar(input)
+}
+
+async function solveForFirstStar (input) {
+  const seq = [...input]
+  const next = () => {
+    for (let i = 1; i < seq.length; i++) {
+      if (seq[seq.length - 1 - i] === seq[seq.length - 1]) {
+        return i
+      }
+    }
+    return 0
+  }
+  while (seq.length < 2020) {
+    seq.push(next())
+  }
+
+  const solution = seq[2019]
+  //  report('Input:', input);
+  report('Solution 1:', solution)
+}
+
+async function solveForSecondStar (input) {
+  const lastSeenIndex = new Map(input.slice(0, -1).map((n, i) => [n, i]))
+  let last = input[input.length - 1]
+  for (let i = input.length; i < 30000000; i++) {
+    const next = i - 1 - lastSeenIndex.get(last) || 0
+    lastSeenIndex.set(last, i - 1)
+    last = next
+  }
+
+  report('Solution 2:', last)
+}
+
+run()
diff --git a/solutions/day15/viewer.html b/solutions/day15/viewer.html
new file mode 100644
index 0000000..d583fae
--- /dev/null
+++ b/solutions/day15/viewer.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Solution Viewer</title>
+    <style>
+      html, body { font-family: sans-serif; }
+      pre { border-radius: 0.5em; padding: 0.5em; background: #eee; }
+    </style>
+    <script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/npm/vue"></script>
+  </head>
+  <body>
+    <div id="viewer">
+      <h1>Solution Viewer ({{ solutionTitle }})</h1>
+      <p>For interesting problems; this page can be used as a dynamic viewer.</p>
+      <h3><a href="./input.txt">input.txt</a></h3>
+      <pre><code>{{ inputText }}</code></pre>
+      <h3><a href="./solution.js">solution.js</a></h3>
+      <pre><code>{{ solutionText }}</code></pre>
+    </div>
+    <script>
+const app = new Vue({
+  el: '#viewer',
+  data: () => {
+    return {
+      solutionText: '[Loading]',
+      inputText: '[Loading]'
+    }
+  },
+  computed: {
+    solutionTitle() {
+      const parts = (document.location + '').split('/')
+      return parts.reverse()[1]
+    }
+  },
+  async mounted () {
+    this.solutionText = (await axios.get('./solution.js')).data
+    this.inputText = (await axios.get('./input.txt')).data
+  }
+})
+    </script>
+  </body>
+</html>
\ No newline at end of file
