diff --git a/exercise/01/animal.cpp b/exercise/01/animal.cpp
new file mode 100644
index 0000000..8391d95
--- /dev/null
+++ b/exercise/01/animal.cpp
@@ -0,0 +1,46 @@
+#include "animal.h"
+
+animal::~animal()
+{
+}
+
+unsigned int insect::legs() const
+{
+	return 6u;
+}
+
+unsigned int bird::legs() const
+{
+	return 2u;
+}
+
+unsigned int spider::legs() const
+{
+	return 8u;
+}
+
+std::wstring cockroach::species() const
+{
+	return std::wstring(L"cockroach");
+}
+
+std::wstring sparrow::species() const
+{
+	return std::wstring(L"sparrow");
+}
+
+std::wstring tarantula::species() const
+{
+	return std::wstring(L"tarantula");
+}
+
+std::unique_ptr<animal> animal_factory(unsigned int id)
+{
+	switch (id)
+	{
+	case 1: return std::make_unique<cockroach>();
+	case 2: return std::make_unique<sparrow>();
+	case 3: return std::make_unique<tarantula>();
+	default: return nullptr;
+	}
+}
diff --git a/exercise/01/animal.h b/exercise/01/animal.h
new file mode 100644
index 0000000..f51d0ac
--- /dev/null
+++ b/exercise/01/animal.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#include <string>
+
+class animal
+{
+public:
+	virtual std::wstring species() const = 0;
+	virtual unsigned int legs() const = 0;
+	virtual ~animal() = 0;
+};
+
+class insect : public animal
+{
+public:
+	unsigned int legs() const override;
+};
+
+class bird : public animal
+{
+public:
+	unsigned int legs() const override;
+};
+
+class spider : public animal
+{
+public:
+	unsigned int legs() const override;
+};
+
+class cockroach : public insect
+{
+public:
+	std::wstring species() const override;
+};
+
+class sparrow : public bird
+{
+public:
+	std::wstring species() const override;
+};
+
+class tarantula : public spider
+{
+public:
+	std::wstring species() const override;
+};
+
+std::unique_ptr<animal> animal_factory(unsigned int id);
diff --git a/exercise/01/animals.sln b/exercise/01/animals.sln
new file mode 100644
index 0000000..1e13d1f
--- /dev/null
+++ b/exercise/01/animals.sln
@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+VisualStudioVersion = 15.0.28010.2050
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "animals", "animals.vcxproj", "{BB15329E-10D8-4740-94BC-64C50BA4EE12}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x86 = Debug|x86
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{BB15329E-10D8-4740-94BC-64C50BA4EE12}.Debug|x86.ActiveCfg = Debug|Win32
+		{BB15329E-10D8-4740-94BC-64C50BA4EE12}.Debug|x86.Build.0 = Debug|Win32
+		{BB15329E-10D8-4740-94BC-64C50BA4EE12}.Release|x86.ActiveCfg = Release|Win32
+		{BB15329E-10D8-4740-94BC-64C50BA4EE12}.Release|x86.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {728A8247-7589-4D4A-BC24-4C2972DB8D3D}
+	EndGlobalSection
+EndGlobal
diff --git a/exercise/01/animals.vcxproj b/exercise/01/animals.vcxproj
index 0c14cbf..a7c1193 100644
--- a/exercise/01/animals.vcxproj
+++ b/exercise/01/animals.vcxproj
@@ -82,13 +82,15 @@
       <AdditionalLibraryDirectories>$(VCInstallDir)UnitTest\lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
     </Link>
   </ItemDefinitionGroup>
-  <ItemGroup>
-    <ClInclude Include="animal.h" />
-  </ItemGroup>
   <ItemGroup>
     <ClCompile Include="animal.cpp" />
+    <ClCompile Include="leg_counter.cpp" />
     <ClCompile Include="test.cpp" />
   </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="animal.h" />
+    <ClInclude Include="leg_counter.h" />
+  </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
diff --git a/exercise/01/animals.vcxproj.filters b/exercise/01/animals.vcxproj.filters
index ad4d9ab..af13239 100644
--- a/exercise/01/animals.vcxproj.filters
+++ b/exercise/01/animals.vcxproj.filters
@@ -15,10 +15,16 @@
     <ClCompile Include="animal.cpp">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="leg_counter.cpp">
+      <Filter>src</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="animal.h">
       <Filter>src</Filter>
     </ClInclude>
+    <ClInclude Include="leg_counter.h">
+      <Filter>src</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/exercise/01/animals.vcxproj.user b/exercise/01/animals.vcxproj.user
new file mode 100644
index 0000000..be25078
--- /dev/null
+++ b/exercise/01/animals.vcxproj.user
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup />
+</Project>
\ No newline at end of file
diff --git a/exercise/01/leg_counter.cpp b/exercise/01/leg_counter.cpp
new file mode 100644
index 0000000..a6c6414
--- /dev/null
+++ b/exercise/01/leg_counter.cpp
@@ -0,0 +1,16 @@
+#include "leg_counter.h"
+
+std::wstring leg_counter::add_animal(std::unique_ptr<animal> animal)
+{
+	if (animal != nullptr)
+	{
+		count += animal->legs();
+		return animal->species();
+	}
+	return std::wstring();
+}
+
+unsigned int leg_counter::legs() const
+{
+	return count;
+}
diff --git a/exercise/01/leg_counter.h b/exercise/01/leg_counter.h
new file mode 100644
index 0000000..ce227eb
--- /dev/null
+++ b/exercise/01/leg_counter.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <string>
+#include "animal.h"
+
+class leg_counter
+{
+private:
+	unsigned int count;
+public:
+	leg_counter() : count(0) {};
+	std::wstring add_animal(std::unique_ptr<animal> animal);
+	unsigned int legs() const;
+};
+
diff --git a/exercise/01/test.cpp b/exercise/01/test.cpp
index f7f2c1f..dad45e8 100644
--- a/exercise/01/test.cpp
+++ b/exercise/01/test.cpp
@@ -2,6 +2,7 @@
 using namespace Microsoft::VisualStudio::CppUnitTestFramework;
 
 #include "animal.h"
+#include "leg_counter.h"
 
 TEST_CLASS(test_animal_hierarchy)
 {