diff --git a/BillDemo/BillDemo.csproj b/BillDemo/BillDemo.csproj
new file mode 100644
index 0000000..21dff5c
--- /dev/null
+++ b/BillDemo/BillDemo.csproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.2</TargetFramework>
+  </PropertyGroup>
+
+</Project>
diff --git a/BillDemo/Program.cs b/BillDemo/Program.cs
new file mode 100644
index 0000000..415ef76
--- /dev/null
+++ b/BillDemo/Program.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace BillDemo {
+  class Program {
+    static void Main(string[] args) {
+      Console.WriteLine("Hello World!");
+    }
+  }
+}
diff --git a/BillDemo/TaskRunner.cs b/BillDemo/TaskRunner.cs
new file mode 100644
index 0000000..1d8ff21
--- /dev/null
+++ b/BillDemo/TaskRunner.cs
@@ -0,0 +1,17 @@
+using ParallelProcessPractice.Core;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BillDemo {
+  class TaskRunner : TaskRunnerBase {
+    public override void Run(IEnumerable<MyTask> tasks) {
+      Parallel.ForEach(tasks, new ParallelOptions { MaxDegreeOfParallelism = 11 }, task => {
+        task.DoStepN(1);
+        task.DoStepN(2);
+        task.DoStepN(3);
+      });
+    }
+  }
+}
diff --git a/BillDemo/TaskRunnerV1.cs b/BillDemo/TaskRunnerV1.cs
new file mode 100644
index 0000000..9a27006
--- /dev/null
+++ b/BillDemo/TaskRunnerV1.cs
@@ -0,0 +1,53 @@
+using ParallelProcessPractice.Core;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Channels;
+using System.Threading.Tasks;
+
+namespace BillDemo {
+  class TaskRunnerV1 : TaskRunnerBase {
+    public override void Run(IEnumerable<MyTask> tasks) {
+
+      Task t0 = Task.Run(async () => { foreach (var task in tasks) { await queues[1].Writer.WriteAsync(task); } queues[1].Writer.Complete(); });
+      Task t1 = DoAllStepNAsync(1);
+      Task t2 = DoAllStepNAsync(2);
+      Task t3 = DoAllStepNAsync(3);
+
+      //Task.WaitAll(tasks.Select(t => Task.Run(async () =>
+      //{
+      //  await this.queues[1].Writer.WriteAsync(t);
+      //})).ToArray());
+
+      //queues[1].Writer.Complete();
+
+      Task.WaitAll(t1, t2, t3);
+    }
+
+    private Channel<MyTask>[] queues = new Channel<MyTask>[3 + 1]
+    {
+            null,
+            Channel.CreateBounded<MyTask>(5),
+            Channel.CreateUnbounded<MyTask>(),
+            Channel.CreateUnbounded<MyTask>(),
+    };
+
+    private async Task DoAllStepNAsync(int step) {
+      bool last = (step == 3);
+      List<Task> ts = new List<Task>();
+      while (await queues[step].Reader.WaitToReadAsync()) {
+        while (queues[step].Reader.TryRead(out MyTask task)) {
+          ts.Add(Task.Run(async () =>
+          {
+            task.DoStepN(step);
+            if (!last)
+              await queues[step + 1].Writer.WriteAsync(task);
+          }));
+        }
+      }
+      Task.WaitAll(ts.ToArray());
+      if (!last)
+        queues[step + 1].Writer.Complete();
+    }
+  }
+}
diff --git a/ParallelProcessPractice.sln b/ParallelProcessPractice.sln
index 387a9fb..611913d 100644
--- a/ParallelProcessPractice.sln
+++ b/ParallelProcessPractice.sln
@@ -47,6 +47,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NathanDemo", "NathanDemo\Na
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "JolinDemo", "JolinDemo\JolinDemo.csproj", "{C58EA4C0-FFEC-43D6-97ED-EF755AE14B64}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "BillDemo", "BillDemo\BillDemo.csproj", "{F080C41B-CBFA-49C8-844F-DA612F43651B}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -117,6 +119,10 @@ Global
 		{C58EA4C0-FFEC-43D6-97ED-EF755AE14B64}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{C58EA4C0-FFEC-43D6-97ED-EF755AE14B64}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{C58EA4C0-FFEC-43D6-97ED-EF755AE14B64}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F080C41B-CBFA-49C8-844F-DA612F43651B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F080C41B-CBFA-49C8-844F-DA612F43651B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F080C41B-CBFA-49C8-844F-DA612F43651B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F080C41B-CBFA-49C8-844F-DA612F43651B}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -136,6 +142,7 @@ Global
 		{1B34613F-9384-4365-A54E-D9719D6E902B} = {B21D6D24-8EC2-497F-AE16-E0155FEE28CE}
 		{CD021A28-2C35-4FAA-BFDC-3E4543F009A0} = {B21D6D24-8EC2-497F-AE16-E0155FEE28CE}
 		{C58EA4C0-FFEC-43D6-97ED-EF755AE14B64} = {B21D6D24-8EC2-497F-AE16-E0155FEE28CE}
+		{F080C41B-CBFA-49C8-844F-DA612F43651B} = {B21D6D24-8EC2-497F-AE16-E0155FEE28CE}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {15051360-3A56-4052-A944-97C62F90EEC6}