diff --git a/BoxList.php b/BoxList.php
index c93460d6..3ab0a057 100644
--- a/BoxList.php
+++ b/BoxList.php
@@ -18,7 +18,15 @@ class BoxList extends \SplMinHeap {
      * @see \SplMinHeap::compare()
      */
     public function compare($aBoxA, $aBoxB) {
-      return $aBoxB->getInnerVolume() - $aBoxA->getInnerVolume();
+      if ($aBoxB->getInnerVolume() > $aBoxA->getInnerVolume()) {
+        return 1;
+      }
+      else if ($aBoxB->getInnerVolume() < $aBoxA->getInnerVolume()) {
+        return -1;
+      }
+      else {
+        return 0;
+      }
     }
 
   }
diff --git a/ItemList.php b/ItemList.php
index a9dad960..0120d1d8 100644
--- a/ItemList.php
+++ b/ItemList.php
@@ -18,7 +18,15 @@ class ItemList extends \SplMaxHeap {
      * @see \SplMaxHeap::compare()
      */
     public function compare($aItemA, $aItemB) {
-      return $aItemA->getVolume() - $aItemB->getVolume();
+      if ($aItemA->getVolume() > $aItemB->getVolume()) {
+        return 1;
+      }
+      else if ($aItemA->getVolume() < $aItemB->getVolume()) {
+        return -1;
+      }
+      else {
+        return 0;
+      }
     }
 
     /**
diff --git a/tests/BoxListTest.php b/tests/BoxListTest.php
index 73b1ca0a..6fafbaae 100644
--- a/tests/BoxListTest.php
+++ b/tests/BoxListTest.php
@@ -26,4 +26,43 @@ function testCompare() {
       }
       self::assertEquals(array($box1,$box3,$box2), $sorted);
     }
+
+    function testIssue14A() {
+      $box1 = new TestBox('Small', 21, 21, 3, 1, 20, 20, 2, 100);
+      $box2 = new TestBox('Large', 1301, 1301, 1301, 1, 1300, 1300, 1300, 1000);
+      $box3 = new TestBox('Medium', 101, 101, 11, 5, 100, 100, 10, 500);
+      $list = new BoxList;
+      $list->insert($box1);
+      $list->insert($box2);
+      $list->insert($box3);
+      $sorted = [];
+      while (!$list->isEmpty()) {
+        $sorted[] = $list->extract();
+      }
+      self::assertEquals(array($box1,$box3,$box2), $sorted);
+    }
+
+    function testIssue14B() {
+      $box1 = new TestBox('Small', 21, 21, 3, 1, 20, 20, 2, 100);
+      $box2 = new TestBox('Large', 1301, 1301, 1301, 1, 1300, 1300, 1300, 1000);
+      $box3 = new TestBox('Medium', 101, 101, 11, 5, 100, 100, 10, 500);
+      $list = new BoxList;
+      $list->insert($box3);
+      $list->insert($box2);
+      $list->insert($box1);
+      $sorted = [];
+      while (!$list->isEmpty()) {
+        $sorted[] = $list->extract();
+      }
+      self::assertEquals(array($box1,$box3,$box2), $sorted);
+      $list = new BoxList;
+      $list->insert($box2);
+      $list->insert($box1);
+      $list->insert($box3);
+      $sorted = [];
+      while (!$list->isEmpty()) {
+        $sorted[] = $list->extract();
+      }
+      self::assertEquals(array($box1,$box3,$box2), $sorted);
+    }
   }