diff --git a/clock/clock_test.php b/clock/clock_test.php
new file mode 100644
index 00000000..678093d0
--- /dev/null
+++ b/clock/clock_test.php
@@ -0,0 +1,113 @@
+<?php
+
+require_once realpath(__DIR__ . '/clock.php');
+
+class ClockTest extends PHPUnit_Framework_TestCase
+{
+    public function testOnTheHour()
+    {
+        $clock = new Clock(8);
+
+        $this->assertEquals('08:00', $clock->__toString());
+    }
+
+    public function testPastTheHour()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(11, 9);
+
+        $this->assertEquals('11:09', $clock->__toString());
+    }
+
+    public function testAddingAFewMinutes()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(10);
+
+        $clock = $clock->add(3);
+
+        $this->assertEquals('10:03', $clock->__toString());
+    }
+
+    public function testAddingOverAnHour()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(10);
+
+        $clock = $clock->add(61);
+
+        $this->assertEquals('11:01', $clock->__toString());
+    }
+
+    public function testWrapAroundAtMidnight()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(23, 30);
+
+        $clock = $clock->add(60);
+
+        $this->assertEquals('00:30', $clock->__toString());
+    }
+
+    public function testSubtractMinutes()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(10);
+
+        $clock = $clock->sub(90);
+
+        $this->assertEquals('08:30', $clock->__toString());
+    }
+
+    public function testWrapAroundBackwards()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(0, 30);
+
+        $clock = $clock->sub(60);
+
+        $this->assertEquals('23:30', $clock->__toString());
+    }
+
+    public function testWrapAroundDay()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(5, 32);
+
+        $clock = $clock->add(25 * 60);
+
+        $this->assertEquals('06:32', $clock->__toString());
+    }
+
+    public function testWrapAroundDayBackwards()
+    {
+        $this->markTestSkipped();
+
+        $clock = new Clock(5, 32);
+
+        $clock = $clock->sub(25 * 60);
+
+        $this->assertEquals('04:32', $clock->__toString());
+    }
+
+    public function testEquivalentClocks()
+    {
+        $this->markTestSkipped();
+
+        $this->assertEquals(new Clock(15, 37), new Clock(15, 37));
+    }
+
+    public function testInequivalentClocks()
+    {
+        $this->markTestSkipped();
+
+        $this->assertNotEquals(new Clock(01, 01), new Clock(18, 32));
+    }
+}
diff --git a/clock/example.php b/clock/example.php
new file mode 100644
index 00000000..720510e7
--- /dev/null
+++ b/clock/example.php
@@ -0,0 +1,61 @@
+<?php
+
+class Clock
+{
+    private $minutes;
+
+    /**
+     * @param int $hour
+     * @param int $minutes
+     */
+    public function __construct($hour, $minutes = 0)
+    {
+        $this->minutes = $hour * 60 + $minutes;
+    }
+
+    /**
+     * Returns a new Clock incremented by $minutes
+     *
+     * @param int $minutes
+     * @return Clock
+     */
+    public function add($minutes)
+    {
+        return $this->build($this->minutes + $minutes);
+    }
+
+    /**
+     * Returns a new Clock deincremented by $minutes
+     *
+     * @param int $minutes
+     * @return Clock
+     */
+    public function sub($minutes)
+    {
+        return $this->build($this->minutes - $minutes);
+    }
+
+    /**
+     * Returns the string representation of the receiver
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        return sprintf('%02d:%02d', $this->minutes / 60, $this->minutes % 60);
+    }
+
+    /**
+     * @param $minutes
+     * @return Clock
+     */
+    private function build($minutes)
+    {
+        if ($minutes < 60) {
+            $minutes += 24 * 60;
+        }
+
+        $hour = floor($minutes / 60);
+        return new Clock($hour < 24 ? $hour : $hour - 24, $minutes % 60);
+    }
+}
diff --git a/config.json b/config.json
index 516dbedb..054f4b3b 100644
--- a/config.json
+++ b/config.json
@@ -5,7 +5,8 @@
   "active": false,
   "problems": [
     "trinary",
-    "wordy"
+    "wordy",
+    "clock"
   ],
   "deprecated": [