diff --git a/gnome-quod/src/boardpanel.h b/gnome-quod/src/boardpanel.h
index 868b2ee..a7a05ec 100644
--- a/gnome-quod/src/boardpanel.h
+++ b/gnome-quod/src/boardpanel.h
@@ -28,8 +28,8 @@
 class BoardPanel : public Gtk::DrawingArea
 {
 public:
-    static const double dx = 1.0;
-    static const double dy = 1.0;
+    static constexpr double dx = 1.0;
+    static constexpr double dy = 1.0;
     static const Glib::ustring NO_BACKGROUND;
 
     BoardPanel (const Board* board);