diff --git a/.gitmodules b/.gitmodules
index 111b48c..f3516a9 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,9 @@
 [submodule "3-Modeling/c++/deps/geometry-central"]
 	path = 3-modeling/c++/deps/geometry-central
 	url = https://github.com/nmwsharp/geometry-central.git
+[submodule "4-LaplacianSmoothing/c++/deps/polyscope"]
+	path = 4-LaplacianSmoothing/c++/deps/polyscope
+	url = https://github.com/nmwsharp/polyscope.git
+[submodule "4-LaplacianSmoothing/c++/deps/geometry-central"]
+	path = 4-LaplacianSmoothing/c++/deps/geometry-central
+	url = https://github.com/nmwsharp/geometry-central.git
diff --git a/4-LaplacianSmoothing/c++/CMakeLists.txt b/4-LaplacianSmoothing/c++/CMakeLists.txt
new file mode 100644
index 0000000..a00cae1
--- /dev/null
+++ b/4-LaplacianSmoothing/c++/CMakeLists.txt
@@ -0,0 +1,67 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(CGDI)
+
+
+# Print the build type
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose the type of build, options are: Debug Release" FORCE)
+endif()
+message(STATUS "cmake build type: ${CMAKE_BUILD_TYPE}")
+
+### Configure the compiler
+# This is a basic, decent setup that should do something sane on most compilers
+
+if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+
+  # using Clang (linux or apple) or GCC
+  message("Using clang/gcc compiler flags")
+  SET(BASE_CXX_FLAGS "-std=c++11 -Wall -Wextra")
+  SET(DISABLED_WARNINGS " -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -Wno-deprecated-declarations -Wno-missing-braces -Wno-unused-private-field")
+  SET(TRACE_INCLUDES " -H -Wno-error=unused-command-line-argument")
+
+  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
+    message("Setting clang-specific options")
+    SET(BASE_CXX_FLAGS "${BASE_CXX_FLAGS} -ferror-limit=3 -fcolor-diagnostics")
+    SET(CMAKE_CXX_FLAGS_DEBUG          "-g3 -fsanitize=address -fno-limit-debug-info")
+  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    message("Setting gcc-specific options")
+    SET(BASE_CXX_FLAGS "${BASE_CXX_FLAGS} -fmax-errors=5")
+    SET(CMAKE_CXX_FLAGS_DEBUG          "-g3")
+    SET(DISABLED_WARNINGS "${DISABLED_WARNINGS} -Wno-maybe-uninitialized -Wno-format-zero-length -Wno-unused-but-set-parameter -Wno-unused-but-set-variable")
+  endif()
+
+  SET(CMAKE_CXX_FLAGS "${BASE_CXX_FLAGS} ${DISABLED_WARNINGS}")
+  SET(CMAKE_CXX_FLAGS_RELEASE        "-O3 -march=native -DNDEBUG")
+
+elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+  # using Visual Studio C++
+  message("Using Visual Studio compiler flags")
+  set(BASE_CXX_FLAGS "${BASE_CXX_FLAGS} /W4")
+  set(BASE_CXX_FLAGS "${BASE_CXX_FLAGS} /MP") # parallel build
+  SET(DISABLED_WARNINGS "${DISABLED_WARNINGS} /wd\"4267\"")  # ignore conversion to smaller type (fires more aggressively than the gcc version, which is annoying)
+  SET(DISABLED_WARNINGS "${DISABLED_WARNINGS} /wd\"4244\"")  # ignore conversion to smaller type (fires more aggressively than the gcc version, which is annoying)
+  SET(DISABLED_WARNINGS "${DISABLED_WARNINGS} /wd\"4305\"")  # ignore truncation on initialization
+  SET(CMAKE_CXX_FLAGS "${BASE_CXX_FLAGS} ${DISABLED_WARNINGS}")
+  set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MD")
+  set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MDd")
+
+  add_definitions(/D "_CRT_SECURE_NO_WARNINGS")
+  add_definitions(-DNOMINMAX)
+  add_definitions(-D_USE_MATH_DEFINES)
+else()
+  # unrecognized
+  message( FATAL_ERROR "Unrecognized compiler [${CMAKE_CXX_COMPILER_ID}]" )
+endif()
+
+
+# == Deps
+add_subdirectory(deps/geometry-central)
+add_subdirectory(deps/polyscope)
+
+# == Build our project stuff
+
+
+add_executable(displayOBJ displayOBJ)
+target_link_libraries(displayOBJ polyscope geometry-central)
+
diff --git a/4-LaplacianSmoothing/c++/deps/geometry-central b/4-LaplacianSmoothing/c++/deps/geometry-central
new file mode 160000
index 0000000..954e993
--- /dev/null
+++ b/4-LaplacianSmoothing/c++/deps/geometry-central
@@ -0,0 +1 @@
+Subproject commit 954e9933a4be27637904b02a2f2fe1cae756e3f9
diff --git a/4-LaplacianSmoothing/c++/deps/polyscope b/4-LaplacianSmoothing/c++/deps/polyscope
new file mode 160000
index 0000000..873e700
--- /dev/null
+++ b/4-LaplacianSmoothing/c++/deps/polyscope
@@ -0,0 +1 @@
+Subproject commit 873e700f22ff1ef91689980a53cbb403c79636bf
diff --git a/4-LaplacianSmoothing/c++/displayOBJ.cpp b/4-LaplacianSmoothing/c++/displayOBJ.cpp
new file mode 100644
index 0000000..ab7160b
--- /dev/null
+++ b/4-LaplacianSmoothing/c++/displayOBJ.cpp
@@ -0,0 +1,33 @@
+#include "geometrycentral/surface/manifold_surface_mesh.h"
+#include "geometrycentral/surface/meshio.h"
+#include "geometrycentral/surface/vertex_position_geometry.h"
+
+#include "polyscope/polyscope.h"
+#include "polyscope/surface_mesh.h"
+
+using namespace geometrycentral;
+using namespace geometrycentral::surface;
+
+// == Geometry-central data
+std::unique_ptr<ManifoldSurfaceMesh> mesh;
+std::unique_ptr<VertexPositionGeometry> geometry;
+
+int main(int argc, char **argv) {
+
+  // Initialize polyscope
+  polyscope::init();
+
+  // Load mesh
+  std::tie(mesh, geometry) = readManifoldSurfaceMesh(argv[1]);
+
+  // Register the mesh with polyscope
+  polyscope::registerSurfaceMesh("Input obj",
+                                 geometry->inputVertexPositions,
+                                 mesh->getFaceVertexList(),
+                                 polyscopePermutations(*mesh));
+  
+  // Give control to the polyscope gui
+  polyscope::show();
+
+  return EXIT_SUCCESS;
+}
diff --git a/4-LaplacianSmoothing/python/testPyGEL.py b/4-LaplacianSmoothing/python/testPyGEL.py
new file mode 100644
index 0000000..f2eea30
--- /dev/null
+++ b/4-LaplacianSmoothing/python/testPyGEL.py
@@ -0,0 +1,31 @@
+import polyscope
+import numpy as np
+from pygel3d import hmesh
+
+m = hmesh.load("../cube.obj")
+print(m.positions())
+
+faces = m.faces()
+
+## Old school
+allfaces=[]
+for f in faces:
+ face=[]
+ for v in m.circulate_face(f):
+     face.append(v)
+ allfaces = allfaces + [face]
+
+## Fancy version
+allfaces2 = [[v for v in m.circulate_face(f)] for f in faces]
+
+polyscope.init()
+
+#Display the vertices as point cloud
+polyscope.register_point_cloud("data", m.positions())
+
+#Display the vertices as mesh
+polyscope.register_surface_mesh("data mesh", m.positions(), allfaces)
+#Display the vertices as mesh
+polyscope.register_surface_mesh("data mesh2", m.positions(), allfaces2)
+
+polyscope.show()