diff --git a/lib/millipede.js b/lib/millipede.js
index e9b29f8..f7d9d72 100644
--- a/lib/millipede.js
+++ b/lib/millipede.js
@@ -26,8 +26,8 @@ var PADDING = [
 function Millipede(size, options) {
     options = options || {};
 
-    this.size = size || 20;
-    this.reverse = options.reverse || false;
+    this.size = size;
+    this.reverse = options.reverse;
     this.horizontal = options.horizontal || false;
     this.position = options.position || 0;
 
@@ -49,7 +49,7 @@ Object.defineProperty(Millipede.prototype, 'size', {
         return this._size;
     },
     set: function (value) {
-        this._size = value;
+        this._size = value || 20;
         this._computePadding();
     }
 });