Implement an alternative way of structuring nodes.

src/FlatLayerVisualisation.hpp

@@ -10,11 +10,17 @@ namespace fmri
     class FlatLayerVisualisation : public LayerVisualisation
     {
     public:
-        explicit FlatLayerVisualisation(const LayerData& layer);
+        enum class Ordering {
+            LINE,
+            SQUARE,
+        };
+
+        explicit FlatLayerVisualisation(const LayerData &layer, Ordering ordering);
 
         void render() override;
 
     private:
+        Ordering ordering;
         std::size_t faceCount;
         std::unique_ptr<float[]> vertexBuffer;
         std::unique_ptr<float[]> colorBuffer;