diff --git a/homework4/starting_point/.idea/workspace.xml b/homework4/starting_point/.idea/workspace.xml
index 00f71ad..701b64c 100644
--- a/homework4/starting_point/.idea/workspace.xml
+++ b/homework4/starting_point/.idea/workspace.xml
@@ -1,391 +1,408 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
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     <generated>
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   <component name="ChangeListManager">
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         <option value="$PROJECT_DIR$/CMakeLists.txt" />
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   </component>
   <component name="TimeTrackingManager">
-    <option name="totallyTimeSpent" value="14534000" />
+    <option name="totallyTimeSpent" value="17554000" />
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   <component name="ToolWindowManager">
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     <entry file="file://$PROJECT_DIR$/compute_temperature.hh">
       <provider selected="true" editor-type-id="text-editor">
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+        <state relative-caret-position="-104" />
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     <entry file="file://$PROJECT_DIR$/particles_factory_interface.hh">
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-    <entry file="file://$PROJECT_DIR$/py_part.cpp">
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-    <entry file="file://$PROJECT_DIR$/material_points_factory.cc">
+    <entry file="file://$PROJECT_DIR$/py_part.cpp">
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\ No newline at end of file
diff --git a/homework4/starting_point/py_part.cpp b/homework4/starting_point/py_part.cpp
index b884181..696885b 100644
--- a/homework4/starting_point/py_part.cpp
+++ b/homework4/starting_point/py_part.cpp
@@ -1,33 +1,40 @@
 #include <functional>
 #include <iostream>
 #include <pybind11/pybind11.h>
 #include "particles_factory_interface.hh"
 #include "planets_factory.hh"
 #include "ping_pong_balls_factory.hh"
 #include "material_points_factory.hh"
 
 namespace py = pybind11;
 
 PYBIND11_MODULE(pypart, m) {
     m.doc() = "pybind particle plugin"; // optional docstring
 
     // wrap the class
     py::class_<ParticlesFactoryInterface>(m, "ParticlesFactoryInterface")
             .def("getInstance", &ParticlesFactoryInterface::getInstance,
-                 py::return_value_policy::reference);
+                    py::return_value_policy::reference);
 
     py::class_<PingPongBallsFactory, ParticlesFactoryInterface>(m, "PingPongBallsFactory")
             .def("getInstance", &PingPongBallsFactory::getInstance,
-                 py::return_value_policy::reference);
+                    py::return_value_policy::reference)
+            .def("createSimulation", &PingPongBallsFactory::createSimulation);
 
     py::class_<PlanetsFactory, ParticlesFactoryInterface>(m, "PlanetsFactory")
             .def("getInstance", &PlanetsFactory::getInstance,
-                 py::return_value_policy::reference);
+                    py::return_value_policy::reference)
+            .def("createSimulation", &PlanetsFactory::createSimulation);
 
     py::class_<MaterialPointsFactory, ParticlesFactoryInterface>(m, "MaterialPointsFactory")
             .def("getInstance", &MaterialPointsFactory::getInstance,
-                 py::return_value_policy::reference);
+                    py::return_value_policy::reference)
+            .def("createSimulation",
+                 (SystemEvolution & (MaterialPointsFactory::*)(const std::string &, Real))
+                 &MaterialPointsFactory::createSimulation
+            )
+            .def("createSimulation", &MaterialPointsFactory::createSimulation<py::function>);
 
 }