diff --git a/src/Math.cppm b/src/Math.cppm
index 1b5d2b5..7feeb57 100644
--- a/src/Math.cppm
+++ b/src/Math.cppm
@@ -124,7 +124,7 @@ struct Box {
   Box() {}
   Box(Rect<T> rect) {
     this->m_data[0] = rect.pos;
-    this->m_data[0] = rect.pos + rect.size;
+    this->m_data[1] = rect.pos + rect.size;
   }
 
 private: