diff --git a/Simulations/main.cpp b/Simulations/main.cpp
index f41c4ad..070d05a 100644
--- a/Simulations/main.cpp
+++ b/Simulations/main.cpp
@@ -23,7 +23,8 @@ using namespace GamePhysics;
 //#define TEMPLATE_DEMO
 //#define MASS_SPRING_SYSTEM
 //#define RIGID_BODY_SYSTEM
-#define SPHERE_SYSTEM
+//#define SPH_SYSTEM
+#define DIFFUSION_SYSTEM
 
 #ifdef TEMPLATE_DEMO
 #include "TemplateSimulator.h"
@@ -32,10 +33,14 @@ using namespace GamePhysics;
 #include "MassSpringSystemSimulator.h"
 #endif
 #ifdef RIGID_BODY_SYSTEM
-#include "RigidBodySystemSimulator.h"
+//#include "RigidBodySystemSimulator.h"
 #endif
-#ifdef SPHERE_SYSTEM
-#include "SphereSystemSimulator.h"
+#ifdef SPH_SYSTEM
+//#include "SPHSystemSimulator.h"
+#endif
+
+#ifdef DIFFUSION_SYSTEM
+#include "DiffusionSimulator.h"
 #endif
 
 DrawingUtilitiesClass * g_pDUC;
@@ -204,7 +209,9 @@ void CALLBACK OnMouse( bool bLeftButtonDown, bool bRightButtonDown, bool bMiddle
 		g_pSimulator->onClick(xPos,yPos);
 	}
 	else
+	{
 		g_pSimulator->onMouse(xPos, yPos);
+	}
 }
 
 
@@ -363,10 +370,13 @@ int main(int argc, char* argv[])
 	g_pSimulator= new MassSpringSystemSimulator();
 #endif
 #ifdef RIGID_BODY_SYSTEM
-	g_pSimulator= new RigidBodySystemSimulator();
+	//g_pSimulator= new RigidBodySystemSimulator();
 #endif
-#ifdef SPHERE_SYSTEM
-	g_pSimulator= new SphereSystemSimulator();
+#ifdef SPH_SYSTEM
+	//g_pSimulator= new SPHSystemSimulator();
+#endif
+#ifdef DIFFUSION_SYSTEM
+	g_pSimulator= new DiffusionSimulator();
 #endif
 	g_pSimulator->reset();