maze in favicon

favicon.php

@@ -0,0 +1,44 @@
+<?php
+header('Content-Type: image/x-icon');
+
+const SIZE = 16;
+const WALL = 1;
+const GROUND = 0;
+
+$favicon     = imagecreatetruecolor(SIZE, SIZE);
+$wallColor   = imagecolorallocate($favicon, 165, 80, 30);
+$groundColor = imagecolorallocate($favicon, 203, 162, 133);
+
+imagefill($favicon, 0, 0, $wallColor);
+
+$maze = array();
+for ($y = 0; $y < SIZE; $y++) {
+    $maze[$y] = array();
+    for ($x = 0; $x < SIZE; $x++) {
+        $maze[$y][$x] = WALL;
+    }
+}
+
+function dig($position) {
+    global $maze;
+    global $favicon;
+    global $groundColor;
+    $directions = [[0, 1], [0, -1], [1, 0], [-1, 0]];
+    shuffle($directions);
+    foreach ($directions as $direction) {
+        $step1 = [$position[0] + $direction[0], $position[1] + $direction[1]];
+        $step2 = [$step1[0] + $direction[0], $step1[1] + $direction[1]];
+        if (0 <= $step2[1] and $step2[1] < SIZE and 0 <= $step2[0] and $step2[0] < SIZE and $maze[$step2[1]][$step2[0]] == WALL) {
+            $maze[$step1[1]][$step1[0]] = GROUND;
+            imagesetpixel($favicon, $step1[0], $step1[1], $groundColor);
+            $maze[$step2[1]][$step2[0]] = GROUND;
+            imagesetpixel($favicon, $step2[0], $step2[1], $groundColor);
+            dig($step2);
+        }
+    }
+}
+
+dig([1, 1]);
+imagebmp($favicon);
+imagedestroy($favicon);
+?>