diff --git a/day_11/part_1.php b/day_11/part_1.php
new file mode 100644
index 0000000..9f617ac
--- /dev/null
+++ b/day_11/part_1.php
@@ -0,0 +1,54 @@
+<?php
+
+$grid = array_map('str_split', explode("\n", file_get_contents('./input.txt')));
+
+$flashes = 0;
+
+for ($i = 0; $i < 100; $i++) {
+    foreach ($grid as $k => $row) {
+        foreach ($row as $j => $cell) {
+            $grid[$k][$j]++;
+        }
+    }
+
+    while(has_more_than_nine($grid)) {
+        foreach ($grid as $k => $row) {
+            foreach ($row as $j => $cell) {
+                if ($grid[$k][$j] > 9) {
+                    foreach (range(-1, 1) as $r) {
+                        foreach (range(-1, 1) as $c) {
+                            if ($r === 0 && $c === 0) {
+                                $grid[$k+$r][$j+$c] = 0;
+                            }
+                            if (
+                                array_key_exists($k+$r, $grid) &&
+                                array_key_exists($j+$c, $grid[$k+$r]) &&
+                                $grid[$k+$r][$j+$c] !== 0
+                            ) {
+                                $grid[$k+$r][$j+$c]++;
+                            }
+                        }
+                    }
+                    $flashes++;
+                }
+            }
+        }
+    }
+
+    echo sprintf('After step %u%s%s%s', $i + 1, "\n", implode("\n", array_map('implode', $grid)), "\n", "\n");
+}
+
+echo $flashes;
+
+function has_more_than_nine($grid)
+{
+    foreach ($grid as $row) {
+        foreach ($row as $cell) {
+            if ($cell > 9) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
\ No newline at end of file
diff --git a/day_11/part_2.php b/day_11/part_2.php
new file mode 100644
index 0000000..3a9dd43
--- /dev/null
+++ b/day_11/part_2.php
@@ -0,0 +1,68 @@
+<?php
+
+$grid = array_map('str_split', explode("\n", file_get_contents('./input.txt')));
+
+$steps = 0;
+
+while (!are_synchronized($grid)) {
+    foreach ($grid as $k => $row) {
+        foreach ($row as $j => $cell) {
+            $grid[$k][$j]++;
+        }
+    }
+
+    while(has_more_than_nine($grid)) {
+        foreach ($grid as $k => $row) {
+            foreach ($row as $j => $cell) {
+                if ($grid[$k][$j] > 9) {
+                    foreach (range(-1, 1) as $r) {
+                        foreach (range(-1, 1) as $c) {
+                            if ($r === 0 && $c === 0) {
+                                $grid[$k+$r][$j+$c] = 0;
+                            }
+                            if (
+                                array_key_exists($k+$r, $grid) &&
+                                array_key_exists($j+$c, $grid[$k+$r]) &&
+                                $grid[$k+$r][$j+$c] !== 0
+                            ) {
+                                $grid[$k+$r][$j+$c]++;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    $steps++;
+
+    echo sprintf('After step %u%s%s%s%s', $steps, "\n", implode("\n", array_map('implode', $grid)), "\n", "\n");
+}
+
+echo $steps;
+
+function has_more_than_nine($grid)
+{
+    foreach ($grid as $row) {
+        foreach ($row as $cell) {
+            if ($cell > 9) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+function are_synchronized($grid)
+{
+    foreach ($grid as $row) {
+        foreach ($row as $cell) {
+            if ($cell !== 0) {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
\ No newline at end of file