diff --git a/lib/cyberarm_engine/vector.rb b/lib/cyberarm_engine/vector.rb
index 8d9b884..8b397f1 100644
--- a/lib/cyberarm_engine/vector.rb
+++ b/lib/cyberarm_engine/vector.rb
@@ -86,11 +86,13 @@ module CyberarmEngine
         @y      == other &&
         @z      == other &&
         @weight == other
-      else
+      elsif other.is_a?(Vector)
         @x      == other.x &&
         @y      == other.y &&
         @z      == other.z &&
         @weight == other.weight
+      else
+        other == self
       end
     end