diff --git a/.gitignore b/.gitignore
index 5ca0973..4befed3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,2 @@
 .DS_Store
-
+.idea
diff --git a/vtk/src/CMakeLists.txt b/vtk/src/CMakeLists.txt
index f4446c2..97f6e2e 100644
--- a/vtk/src/CMakeLists.txt
+++ b/vtk/src/CMakeLists.txt
@@ -42,6 +42,8 @@ add_executable(VtkBase MACOSX_BUNDLE main.cpp
   helperClasses/LGlyphLayer.h
   helperClasses/Program.cpp
   helperClasses/Program.h
+        helperClasses/SpawnPointCallback.h
+        helperClasses/SpawnPointCallback.cpp
 )
 
 execute_process(
diff --git a/vtk/src/helperClasses/LGlyphLayer.cpp b/vtk/src/helperClasses/LGlyphLayer.cpp
index bec5866..005439d 100644
--- a/vtk/src/helperClasses/LGlyphLayer.cpp
+++ b/vtk/src/helperClasses/LGlyphLayer.cpp
@@ -1,4 +1,5 @@
 #include "LGlyphLayer.h"
+#include "SpawnPointCallback.h"
 #include <vtkActor2D.h>
 #include <vtkGlyph2D.h>
 #include <vtkGlyphSource2D.h>
@@ -6,6 +7,17 @@
 #include <vtkPolyDataMapper2D.h>
 #include <vtkProperty2D.h>
 #include <vtkVertexGlyphFilter.h>
+#include <vtkInteractorStyle.h>
+#include <vtkInteractorStyleUser.h>
+
+
+vtkSmartPointer<SpawnPointCallback> LGlyphLayer::createSpawnPointCallback() {
+    auto newPointCallBack = vtkSmartPointer<SpawnPointCallback>::New();
+    newPointCallBack->setData(data);
+    newPointCallBack->setPoints(points);
+    return newPointCallBack;
+}
+
 
 // TODO: add interactionStyle functionality
 // TODO: add timer + advection (probably from the program class not here)
diff --git a/vtk/src/helperClasses/LGlyphLayer.h b/vtk/src/helperClasses/LGlyphLayer.h
index e13257c..edc751d 100644
--- a/vtk/src/helperClasses/LGlyphLayer.h
+++ b/vtk/src/helperClasses/LGlyphLayer.h
@@ -2,7 +2,9 @@
 #define LGLYPHLAYER_H
 
 #include "Layer.h"
+#include "SpawnPointCallback.h"
 #include <vtkPolyData.h>
+#include <vtkInteractorStyle.h>
 
 /** Implements the Layer class for the case of a Lagrangian visualization.
   * Specifically, this class models the Lagrangian particles in the simulation using the 'glyph' mark and 'transparency' channel to denote age.
@@ -13,6 +15,7 @@ private:
   vtkSmartPointer<vtkPolyData> data;
 
 
+
 public:
   /** Constructor.
     */
@@ -27,6 +30,7 @@ public:
     */
   void updateData(int t) override;
 
+  vtkSmartPointer<SpawnPointCallback> createSpawnPointCallback();
 };
 
 #endif
diff --git a/vtk/src/helperClasses/Program.cpp b/vtk/src/helperClasses/Program.cpp
index 8f5a578..1451cee 100644
--- a/vtk/src/helperClasses/Program.cpp
+++ b/vtk/src/helperClasses/Program.cpp
@@ -1,8 +1,10 @@
 #include <vtkRenderWindow.h>
 #include <vtkNew.h>
 #include <vtkCallbackCommand.h>
+#include <vtkInteractorStyleUser.h>
 
 #include "Program.h"
+#include "SpawnPointCallback.h"
 
 
 void Program::setWinProperties() {
@@ -13,6 +15,8 @@ void Program::setWinProperties() {
   this->interact->SetRenderWindow(this->win);
   this->interact->Initialize();
 
+  vtkNew<vtkInteractorStyleUser> style;
+  interact->SetInteractorStyle(style);
 }
 
 void Program::CallbackFunction(vtkObject* caller, long unsigned int eventId, void* clientData, void* callData) {
@@ -20,7 +24,6 @@ void Program::CallbackFunction(vtkObject* caller, long unsigned int eventId, voi
   ((Program *)clientData)->win->Render();
 }
 
-
 void Program::setupTimer() {
   vtkNew<vtkCallbackCommand> callback;
   callback->SetCallback(this->CallbackFunction);
@@ -29,7 +32,6 @@ void Program::setupTimer() {
   this->interact->CreateRepeatingTimer(17); // 60 fps == 1000 / 60 == 16.7 ms per frame
 }
 
-
 Program::Program(Layer *bg, Layer *e, Layer *l) : background(bg), euler(e), lagrange(l), win(), interact() {
   this->win = vtkSmartPointer<vtkRenderWindow>::New();
   this->interact = vtkSmartPointer<vtkRenderWindowInteractor>::New();
@@ -64,7 +66,11 @@ void Program::setLagrange(Layer *l) {
   this->win->AddRenderer(l->getLayer());
 }
 
-// void Program::addInteractionStyle(vtkInteractorStyle style);
+void Program::setLagrangeInteractor(SpawnPointCallback *cb){
+    interact->AddObserver(vtkCommand::LeftButtonPressEvent, cb);
+    interact->AddObserver(vtkCommand::LeftButtonReleaseEvent, cb);
+    interact->AddObserver(vtkCommand::MouseMoveEvent, cb);
+}
 
 
 void Program::render() {
diff --git a/vtk/src/helperClasses/Program.h b/vtk/src/helperClasses/Program.h
index 35013d5..002c977 100644
--- a/vtk/src/helperClasses/Program.h
+++ b/vtk/src/helperClasses/Program.h
@@ -6,6 +6,7 @@
 #include <vtkRenderer.h>
 
 #include "Layer.h"
+#include "SpawnPointCallback.h"
 
 class Program {
 private:
@@ -25,8 +26,9 @@ public:
   void setBackground(Layer *bg);
   void setEuler(Layer *e);
   void setLagrange(Layer *l);
+  void setLagrangeInteractor(SpawnPointCallback *cb);
 
-  // void addInteractionStyle(vtkInteractorStyle style);
+//  void addObserver(vtkInteractorStyle *style);
 
   void render();
 };
diff --git a/vtk/src/helperClasses/SpawnPointCallback.cpp b/vtk/src/helperClasses/SpawnPointCallback.cpp
new file mode 100644
index 0000000..14dbc49
--- /dev/null
+++ b/vtk/src/helperClasses/SpawnPointCallback.cpp
@@ -0,0 +1,60 @@
+#include "SpawnPointCallback.h"
+
+#include <vtkVertex.h>
+#include <vtkRenderer.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkSmartPointer.h>
+#include <vtkCommand.h>
+#include <vtkRenderWindow.h>
+
+void convertDisplayToWorld(vtkRenderer* renderer, int x, int y, double *worldPos) {
+    double displayPos[3] = {static_cast<double>(x), static_cast<double>(y), 0.0};
+    renderer->SetDisplayPoint(displayPos);
+    renderer->DisplayToWorld();
+    renderer->GetWorldPoint(worldPos);
+}
+
+void SpawnPointCallback::Execute(vtkObject *caller, unsigned long evId, void *callData) {
+    // Note the use of reinterpret_cast to cast the caller to the expected type.
+    auto interactor = reinterpret_cast<vtkRenderWindowInteractor *>(caller);
+
+    if (evId == vtkCommand::LeftButtonPressEvent) {
+        dragging = true;
+    }
+    if (evId == vtkCommand::LeftButtonReleaseEvent) {
+        dragging = false;
+    }
+    if (!dragging) {
+        return;
+    }
+
+    int x, y;
+    interactor->GetEventPosition(x, y);
+
+    vtkIdType id = points->InsertNextPoint(x, y, 0);
+    data->SetPoints(points);
+
+    vtkSmartPointer<vtkVertex> vertex = vtkSmartPointer<vtkVertex>::New();
+    vertex->GetPointIds()->SetId(0, id);
+
+    vtkSmartPointer<vtkCellArray> vertices = vtkSmartPointer<vtkCellArray>::New();
+    vertices->InsertNextCell(vertex);
+    data->SetVerts(vertices);
+//    data->Modified(); // These might be needed im not sure.
+//    ren->GetRenderWindow()->Render();
+}
+
+
+SpawnPointCallback::SpawnPointCallback() : data(nullptr), points(nullptr) {}
+
+SpawnPointCallback *SpawnPointCallback::New() {
+    return new SpawnPointCallback;
+}
+
+void SpawnPointCallback::setData(const vtkSmartPointer<vtkPolyData> &data) {
+    this->data = data;
+}
+
+void SpawnPointCallback::setPoints(const vtkSmartPointer<vtkPoints> &points) {
+    this->points = points;
+}
\ No newline at end of file
diff --git a/vtk/src/helperClasses/SpawnPointCallback.h b/vtk/src/helperClasses/SpawnPointCallback.h
new file mode 100644
index 0000000..99ab160
--- /dev/null
+++ b/vtk/src/helperClasses/SpawnPointCallback.h
@@ -0,0 +1,31 @@
+#ifndef VTKBASE_SPAWNPOINTCALLBACK_H
+#define VTKBASE_SPAWNPOINTCALLBACK_H
+
+
+#include <vtkCallbackCommand.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkPoints.h>
+#include <vtkPolyData.h>
+
+class SpawnPointCallback : public vtkCallbackCommand {
+
+public:
+    static SpawnPointCallback *New();
+    SpawnPointCallback();
+
+    void setPoints(const vtkSmartPointer<vtkPoints> &points);
+
+    void setData(const vtkSmartPointer<vtkPolyData> &data);
+
+private:
+    vtkSmartPointer<vtkPolyData> data;
+    vtkSmartPointer<vtkPoints> points;
+public:
+
+private:
+    void Execute(vtkObject *caller, unsigned long evId, void *callData) override;
+    bool dragging = false;
+};
+
+
+#endif //VTKBASE_SPAWNPOINTCALLBACK_H
diff --git a/vtk/src/main.cpp b/vtk/src/main.cpp
index d5aa31d..78b1a3a 100644
--- a/vtk/src/main.cpp
+++ b/vtk/src/main.cpp
@@ -23,6 +23,7 @@ int main() {
   l->spoofPoints();
 
   auto program = new Program(bg, e, l);
+  program->setLagrangeInteractor(l->createSpawnPointCallback());
   program->render();
 
   return EXIT_SUCCESS;