diff --git a/csharp/Feb22/Feb22.sln b/csharp/Feb22/Feb22.sln
new file mode 100644
index 0000000..d49791e
--- /dev/null
+++ b/csharp/Feb22/Feb22.sln
@@ -0,0 +1,16 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "cn-0221", "cn-0221\cn-0221.csproj", "{80105805-C505-4A25-BAE2-1F8AC43D53E7}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{80105805-C505-4A25-BAE2-1F8AC43D53E7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{80105805-C505-4A25-BAE2-1F8AC43D53E7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{80105805-C505-4A25-BAE2-1F8AC43D53E7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{80105805-C505-4A25-BAE2-1F8AC43D53E7}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal
diff --git a/csharp/Feb22/cn-0221/Program.cs b/csharp/Feb22/cn-0221/Program.cs
new file mode 100644
index 0000000..2de9a41
--- /dev/null
+++ b/csharp/Feb22/cn-0221/Program.cs
@@ -0,0 +1,29 @@
+namespace cn_0221;
+
+public class Solution {
+	public static string PushDominoes(string dominoes) {
+		var q = new Queue<int>();
+
+		var n = dominoes.Length;
+		for (int i = 0; i < n; ++i) {
+			if ('.' != dominoes[i]) {
+				q.Enqueue(i);
+				q.Enqueue(0);
+			}
+		}
+
+		var result = new int[n];
+		var lastModified = new int[n];
+		while (q.Count > 0) {
+			var position = q.Dequeue();
+			var timePoint = q.Dequeue();
+			
+		}
+		
+		return "test";
+	}
+
+	public static void Main() {
+		// empty
+	}
+}
\ No newline at end of file
diff --git a/csharp/Feb22/cn-0221/cn-0221.csproj b/csharp/Feb22/cn-0221/cn-0221.csproj
new file mode 100644
index 0000000..1491ef2
--- /dev/null
+++ b/csharp/Feb22/cn-0221/cn-0221.csproj
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net6.0</TargetFramework>
+        <RootNamespace>cn_0221</RootNamespace>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>