diff --git a/vtk/src/Program.cpp b/vtk/src/Program.cpp
index f5d1a93..bcb3e61 100644
--- a/vtk/src/Program.cpp
+++ b/vtk/src/Program.cpp
@@ -37,6 +37,7 @@ void Program::setupTimer() {
   auto callback = vtkSmartPointer<TimerCallbackCommand>::New(this);
   callback->SetClientData(this);
   this->interact->AddObserver(vtkCommand::TimerEvent, callback);
+  this->interact->AddObserver(vtkCommand::KeyPressEvent, callback);
   this->interact->CreateRepeatingTimer(17); // 60 fps == 1000 / 60 == 16.7 ms per frame
 }
 
diff --git a/vtk/src/commands/TimerCallbackCommand.cpp b/vtk/src/commands/TimerCallbackCommand.cpp
index 94e9de9..8e91b58 100644
--- a/vtk/src/commands/TimerCallbackCommand.cpp
+++ b/vtk/src/commands/TimerCallbackCommand.cpp
@@ -7,10 +7,16 @@ TimerCallbackCommand::TimerCallbackCommand() : dt(3600), maxTime(3600*24*365), t
 TimerCallbackCommand* TimerCallbackCommand::New(Program *program) {
   TimerCallbackCommand *cb = new TimerCallbackCommand();
   cb->setProgram(program);
+  cb->setPaused(false);
   return cb;
 }
 
 void TimerCallbackCommand::Execute(vtkObject* caller, unsigned long eventId, void* vtkNotUsed(callData)) {
+  auto intr = reinterpret_cast<vtkRenderWindowInteractor *>(caller);
+  
+  if (eventId == vtkCommand::KeyPressEvent and not strcmp("space", intr->GetKeySym())) {
+    this->paused = ! this->paused;
+  } else if (eventId == vtkCommand::TimerEvent and not this->paused) {
   this->time += this->dt;
 
   if (this->time >= this->maxTime) {
@@ -19,10 +25,16 @@ void TimerCallbackCommand::Execute(vtkObject* caller, unsigned long eventId, voi
   }
 
   this->program->updateData(this->time);
-}
+  }
 
+}
 
 
 void TimerCallbackCommand::setProgram(Program *program) {
   this->program = program;
 }
+
+
+void TimerCallbackCommand::setPaused(const bool val) {
+  this->paused = val;
+}
diff --git a/vtk/src/commands/TimerCallbackCommand.h b/vtk/src/commands/TimerCallbackCommand.h
index 618c7bf..2ff65ea 100644
--- a/vtk/src/commands/TimerCallbackCommand.h
+++ b/vtk/src/commands/TimerCallbackCommand.h
@@ -11,11 +11,13 @@ public:
   void Execute(vtkObject* caller, unsigned long eventId, void* vtkNotUsed(callData)) override;
 
   void setProgram(Program *program);
+  void setPaused(const bool val);
 
 private:
   int time;
   int dt;
   int maxTime;
+  bool paused;
   Program *program;
 };