diff --git a/.gitignore b/.gitignore
index d87d4be..46497a6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ spec/reports
 test/tmp
 test/version_tmp
 tmp
+.idea/
\ No newline at end of file
diff --git a/Gemfile b/Gemfile
deleted file mode 100644
index 96affbd..0000000
--- a/Gemfile
+++ /dev/null
@@ -1,5 +0,0 @@
-source 'https://rubygems.org'
-
-gem 'rake'
-gem 'albacore'
-gem 'rubyzip',  "~> 0.9.9"
diff --git a/Rakefile b/Rakefile
deleted file mode 100644
index 58a4c55..0000000
--- a/Rakefile
+++ /dev/null
@@ -1,24 +0,0 @@
-require 'albacore'
-
-desc "build using msbuild"
-msbuild :build do |msb|
-    msb.properties :configuration => :Debug
-    msb.targets :Clean, :Rebuild
-    msb.verbosity = 'quiet'
-    msb.solution =File.join("UKanren", "UKanren.sln")
-end
-
-task :core_copy_to_nuspec => [:build] do
-    output_directory_lib = File.join('nuget',"lib/Net40/")
-    mkdir_p output_directory_lib
-    cp Dir.glob(File.join("UKanren/UKanren/bin/Debug/*.dll")), output_directory_lib
-end
-
-desc "create the nuget package"
-task :nugetpack => [:core_copy_to_nuspec] do |nuget|
-    cd File.join("nuget") do
-        sh "..\\UKanren\\.nuget\\NuGet.exe pack MikroKanren.nuspec"
-    end
-end
-
-
diff --git a/UKanren/.nuget/NuGet.Config b/UKanren/.nuget/NuGet.Config
deleted file mode 100644
index 67f8ea0..0000000
--- a/UKanren/.nuget/NuGet.Config
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<configuration>
-  <solution>
-    <add key="disableSourceControlIntegration" value="true" />
-  </solution>
-</configuration>
\ No newline at end of file
diff --git a/UKanren/.nuget/NuGet.exe b/UKanren/.nuget/NuGet.exe
deleted file mode 100644
index c41a0d0..0000000
Binary files a/UKanren/.nuget/NuGet.exe and /dev/null differ
diff --git a/UKanren/.nuget/NuGet.targets b/UKanren/.nuget/NuGet.targets
deleted file mode 100644
index 3f8c37b..0000000
--- a/UKanren/.nuget/NuGet.targets
+++ /dev/null
@@ -1,144 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-    <PropertyGroup>
-        <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">$(MSBuildProjectDirectory)\..\</SolutionDir>
-
-        <!-- Enable the restore command to run before builds -->
-        <RestorePackages Condition="  '$(RestorePackages)' == '' ">false</RestorePackages>
-
-        <!-- Property that enables building a package from a project -->
-        <BuildPackage Condition=" '$(BuildPackage)' == '' ">false</BuildPackage>
-
-        <!-- Determines if package restore consent is required to restore packages -->
-        <RequireRestoreConsent Condition=" '$(RequireRestoreConsent)' != 'false' ">true</RequireRestoreConsent>
-
-        <!-- Download NuGet.exe if it does not already exist -->
-        <DownloadNuGetExe Condition=" '$(DownloadNuGetExe)' == '' ">false</DownloadNuGetExe>
-    </PropertyGroup>
-
-    <ItemGroup Condition=" '$(PackageSources)' == '' ">
-        <!-- Package sources used to restore packages. By default, registered sources under %APPDATA%\NuGet\NuGet.Config will be used -->
-        <!-- The official NuGet package source (https://www.nuget.org/api/v2/) will be excluded if package sources are specified and it does not appear in the list -->
-        <!--
-            <PackageSource Include="https://www.nuget.org/api/v2/" />
-            <PackageSource Include="https://my-nuget-source/nuget/" />
-        -->
-    </ItemGroup>
-
-    <PropertyGroup Condition=" '$(OS)' == 'Windows_NT'">
-        <!-- Windows specific commands -->
-        <NuGetToolsPath>$([System.IO.Path]::Combine($(SolutionDir), ".nuget"))</NuGetToolsPath>
-    </PropertyGroup>
-
-    <PropertyGroup Condition=" '$(OS)' != 'Windows_NT'">
-        <!-- We need to launch nuget.exe with the mono command if we're not on windows -->
-        <NuGetToolsPath>$(SolutionDir).nuget</NuGetToolsPath>
-    </PropertyGroup>
-
-    <PropertyGroup>
-        <PackagesProjectConfig Condition=" '$(OS)' == 'Windows_NT'">$(MSBuildProjectDirectory)\packages.$(MSBuildProjectName.Replace(' ', '_')).config</PackagesProjectConfig>
-        <PackagesProjectConfig Condition=" '$(OS)' != 'Windows_NT'">$(MSBuildProjectDirectory)\packages.$(MSBuildProjectName).config</PackagesProjectConfig>
-    </PropertyGroup>
-
-    <PropertyGroup>
-      <PackagesConfig Condition="Exists('$(MSBuildProjectDirectory)\packages.config')">$(MSBuildProjectDirectory)\packages.config</PackagesConfig>
-      <PackagesConfig Condition="Exists('$(PackagesProjectConfig)')">$(PackagesProjectConfig)</PackagesConfig>
-    </PropertyGroup>
-    
-    <PropertyGroup>
-        <!-- NuGet command -->
-        <NuGetExePath Condition=" '$(NuGetExePath)' == '' ">$(NuGetToolsPath)\NuGet.exe</NuGetExePath>
-        <PackageSources Condition=" $(PackageSources) == '' ">@(PackageSource)</PackageSources>
-
-        <NuGetCommand Condition=" '$(OS)' == 'Windows_NT'">"$(NuGetExePath)"</NuGetCommand>
-        <NuGetCommand Condition=" '$(OS)' != 'Windows_NT' ">mono --runtime=v4.0.30319 "$(NuGetExePath)"</NuGetCommand>
-
-        <PackageOutputDir Condition="$(PackageOutputDir) == ''">$(TargetDir.Trim('\\'))</PackageOutputDir>
-
-        <RequireConsentSwitch Condition=" $(RequireRestoreConsent) == 'true' ">-RequireConsent</RequireConsentSwitch>
-        <NonInteractiveSwitch Condition=" '$(VisualStudioVersion)' != '' AND '$(OS)' == 'Windows_NT' ">-NonInteractive</NonInteractiveSwitch>
-
-        <PaddedSolutionDir Condition=" '$(OS)' == 'Windows_NT'">"$(SolutionDir) "</PaddedSolutionDir>
-        <PaddedSolutionDir Condition=" '$(OS)' != 'Windows_NT' ">"$(SolutionDir)"</PaddedSolutionDir>
-
-        <!-- Commands -->
-        <RestoreCommand>$(NuGetCommand) install "$(PackagesConfig)" -source "$(PackageSources)"  $(NonInteractiveSwitch) $(RequireConsentSwitch) -solutionDir $(PaddedSolutionDir)</RestoreCommand>
-        <BuildCommand>$(NuGetCommand) pack "$(ProjectPath)" -Properties "Configuration=$(Configuration);Platform=$(Platform)" $(NonInteractiveSwitch) -OutputDirectory "$(PackageOutputDir)" -symbols</BuildCommand>
-
-        <!-- We need to ensure packages are restored prior to assembly resolve -->
-        <BuildDependsOn Condition="$(RestorePackages) == 'true'">
-            RestorePackages;
-            $(BuildDependsOn);
-        </BuildDependsOn>
-
-        <!-- Make the build depend on restore packages -->
-        <BuildDependsOn Condition="$(BuildPackage) == 'true'">
-            $(BuildDependsOn);
-            BuildPackage;
-        </BuildDependsOn>
-    </PropertyGroup>
-
-    <Target Name="CheckPrerequisites">
-        <!-- Raise an error if we're unable to locate nuget.exe  -->
-        <Error Condition="'$(DownloadNuGetExe)' != 'true' AND !Exists('$(NuGetExePath)')" Text="Unable to locate '$(NuGetExePath)'" />
-        <!--
-        Take advantage of MsBuild's build dependency tracking to make sure that we only ever download nuget.exe once.
-        This effectively acts as a lock that makes sure that the download operation will only happen once and all
-        parallel builds will have to wait for it to complete.
-        -->
-        <MsBuild Targets="_DownloadNuGet" Projects="$(MSBuildThisFileFullPath)" Properties="Configuration=NOT_IMPORTANT;DownloadNuGetExe=$(DownloadNuGetExe)" />
-    </Target>
-
-    <Target Name="_DownloadNuGet">
-        <DownloadNuGet OutputFilename="$(NuGetExePath)" Condition=" '$(DownloadNuGetExe)' == 'true' AND !Exists('$(NuGetExePath)')" />
-    </Target>
-
-    <Target Name="RestorePackages" DependsOnTargets="CheckPrerequisites">        
-        <Exec Command="$(RestoreCommand)"
-              Condition="'$(OS)' != 'Windows_NT' And Exists('$(PackagesConfig)')" />
-
-        <Exec Command="$(RestoreCommand)"
-              LogStandardErrorAsError="true"
-              Condition="'$(OS)' == 'Windows_NT' And Exists('$(PackagesConfig)')" />
-    </Target>
-
-    <Target Name="BuildPackage" DependsOnTargets="CheckPrerequisites">
-        <Exec Command="$(BuildCommand)"
-              Condition=" '$(OS)' != 'Windows_NT' " />
-
-        <Exec Command="$(BuildCommand)"
-              LogStandardErrorAsError="true"
-              Condition=" '$(OS)' == 'Windows_NT' " />
-    </Target>
-
-    <UsingTask TaskName="DownloadNuGet" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
-        <ParameterGroup>
-            <OutputFilename ParameterType="System.String" Required="true" />
-        </ParameterGroup>
-        <Task>
-            <Reference Include="System.Core" />
-            <Using Namespace="System" />
-            <Using Namespace="System.IO" />
-            <Using Namespace="System.Net" />
-            <Using Namespace="Microsoft.Build.Framework" />
-            <Using Namespace="Microsoft.Build.Utilities" />
-            <Code Type="Fragment" Language="cs">
-                <![CDATA[
-                try {
-                    OutputFilename = Path.GetFullPath(OutputFilename);
-
-                    Log.LogMessage("Downloading latest version of NuGet.exe...");
-                    WebClient webClient = new WebClient();
-                    webClient.DownloadFile("https://www.nuget.org/nuget.exe", OutputFilename);
-
-                    return true;
-                }
-                catch (Exception ex) {
-                    Log.LogErrorFromException(ex);
-                    return false;
-                }
-            ]]>
-            </Code>
-        </Task>
-    </UsingTask>
-</Project>
diff --git a/UKanren/.nuget/packages.config b/UKanren/.nuget/packages.config
deleted file mode 100644
index 7025a72..0000000
--- a/UKanren/.nuget/packages.config
+++ /dev/null
@@ -1,4 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<packages>
-  <package id="NUnit.Runners" version="2.6.3" />
-</packages>
\ No newline at end of file
diff --git a/UKanren/Tests/Tests.csproj b/UKanren/Tests/Tests.csproj
index dd119e2..ef19d43 100644
--- a/UKanren/Tests/Tests.csproj
+++ b/UKanren/Tests/Tests.csproj
@@ -1,90 +1,28 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProjectGuid>{0776BA22-191E-4C15-AA59-F9077472CB82}</ProjectGuid>
-    <OutputType>Library</OutputType>
-    <AppDesignerFolder>Properties</AppDesignerFolder>
-    <RootNamespace>Tests</RootNamespace>
-    <AssemblyName>Tests</AssemblyName>
-    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
-    <FileAlignment>512</FileAlignment>
-    <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\</SolutionDir>
+    <TargetFramework>net5.0</TargetFramework>
     <RestorePackages>true</RestorePackages>
-    <TargetFrameworkProfile />
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
-    <DebugSymbols>true</DebugSymbols>
-    <DebugType>full</DebugType>
-    <Optimize>false</Optimize>
-    <OutputPath>bin\Debug\</OutputPath>
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\Release\</OutputPath>
-    <DefineConstants>TRACE</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
+    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
+    <IsPackable>false</IsPackable>
   </PropertyGroup>
   <PropertyGroup>
     <StartupObject />
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="nunit.framework, Version=2.6.2.12296, Culture=neutral, PublicKeyToken=96d09a1eb7f44a77, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\packages\NUnit.2.6.3\lib\nunit.framework.dll</HintPath>
-    </Reference>
-    <Reference Include="System" />
-    <Reference Include="System.Core" />
-    <Reference Include="Microsoft.CSharp" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="Describe_Core.cs" />
-    <Compile Include="Describe_Lisp_assp.cs" />
-    <Compile Include="Describe_Lisp_car.cs" />
-    <Compile Include="Describe_Lisp_cdr.cs" />
-    <Compile Include="Describe_Lisp_cons.cs" />
-    <Compile Include="Describe_Lisp_length.cs" />
-    <Compile Include="Describe_Lisp_list.cs" />
-    <Compile Include="Describe_Lisp_map.cs" />
-    <Compile Include="Describe_Lisp_spec.cs" />
-    <Compile Include="Describe_MiniKanren_wrappers.cs" />
-    <Compile Include="Describe_pull.cs" />
-    <Compile Include="TestHelper.cs" />
-    <Compile Include="Describe_Cons_ctor.cs" />
-    <Compile Include="Describe_cons_equals.cs" />
-    <Compile Include="Describe_Cons_ToString.cs" />
-    <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="TestExtensions.cs" />
+    <ProjectReference Include="..\UKanren\UKanren.csproj" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="packages.config" />
+    <PackageReference Include="NUnit" Version="3.12.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.16.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0"/>
   </ItemGroup>
   <ItemGroup>
-    <ProjectReference Include="..\UKanren\UKanren.csproj">
-      <Project>{56f93cdc-b1b4-416c-8880-c956676b281a}</Project>
-      <Name>UKanren</Name>
-    </ProjectReference>
+    <Compile Remove="Properties/AssemblyInfo.cs" />
   </ItemGroup>
-  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />
-  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
-    <PropertyGroup>
-      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
-    </PropertyGroup>
-    <Error Condition="!Exists('$(SolutionDir)\.nuget\NuGet.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\.nuget\NuGet.targets'))" />
-  </Target>
-  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
-       Other similar extension points exist, see Microsoft.Common.targets.
-  <Target Name="BeforeBuild">
-  </Target>
-  <Target Name="AfterBuild">
-  </Target>
-  -->
 </Project>
\ No newline at end of file
diff --git a/UKanren/UKanren/UKanren.csproj b/UKanren/UKanren/UKanren.csproj
index 71e283b..c7052db 100644
--- a/UKanren/UKanren/UKanren.csproj
+++ b/UKanren/UKanren/UKanren.csproj
@@ -1,57 +1,18 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProjectGuid>{56F93CDC-B1B4-416C-8880-C956676B281A}</ProjectGuid>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <OutputType>Library</OutputType>
-    <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>MicroKanren</RootNamespace>
     <AssemblyName>MicroKanren</AssemblyName>
-    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
-    <FileAlignment>512</FileAlignment>
-    <TargetFrameworkProfile />
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
-    <DebugSymbols>true</DebugSymbols>
-    <DebugType>full</DebugType>
-    <Optimize>false</Optimize>
-    <OutputPath>bin\Debug\</OutputPath>
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\Release\</OutputPath>
-    <DefineConstants>TRACE</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
+    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="System" />
-    <Reference Include="System.Core" />
-    <Reference Include="Microsoft.CSharp" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="EmptyPair.cs" />
-    <Compile Include="Pair.cs" />
-    <Compile Include="Core.cs" />
-    <Compile Include="Lisp.cs" />
-    <Compile Include="ObjectExtensions.cs" />
-    <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="Symbol.cs" />
-    <Compile Include="TypeMatch.cs" />
-    <Compile Include="Var.cs" />
+    <Compile Remove="Properties/AssemblyInfo.cs" />
   </ItemGroup>
-  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
-       Other similar extension points exist, see Microsoft.Common.targets.
-  <Target Name="BeforeBuild">
-  </Target>
-  <Target Name="AfterBuild">
-  </Target>
-  -->
 </Project>
\ No newline at end of file