diff --git a/src/Direct3D12/03_DrawQuad/DrawQuadApp.cs b/src/Direct3D12/03_DrawQuad/DrawQuadApp.cs
index 72cf229..6e667b4 100644
--- a/src/Direct3D12/03_DrawQuad/DrawQuadApp.cs
+++ b/src/Direct3D12/03_DrawQuad/DrawQuadApp.cs
@@ -90,7 +90,7 @@ protected override void OnRender()
 
         // Vertex Buffer
         int stride = VertexPositionColor.SizeInBytes;
-        int vertexBufferSize = 3 * stride;
+        int vertexBufferSize = 4 * stride;
         CommandList.IASetVertexBuffers(0, new VertexBufferView(_vertexBuffer.GPUVirtualAddress, vertexBufferSize, stride));
 
         // Index Buffer