diff --git a/OpenNest.WinForms.Tests/Controls/SeparatorPenLifetimeTests.cs b/OpenNest.WinForms.Tests/Controls/SeparatorPenLifetimeTests.cs
index e65f7009..ebc6bbd0 100644
--- a/OpenNest.WinForms.Tests/Controls/SeparatorPenLifetimeTests.cs
+++ b/OpenNest.WinForms.Tests/Controls/SeparatorPenLifetimeTests.cs
@@ -75,7 +75,7 @@ public class SeparatorPenLifetimeTests
         horizontal ? new HorizontalLine() : new VerticalLine();
 
     private static Pen GetPen(Control control, string name) =>
-        Assert.IsType<Pen>(control.GetType()
+        Assert.IsType<Pen>(typeof(SeparatorLine)
             .GetField(name, BindingFlags.Instance | BindingFlags.NonPublic)!.GetValue(control));
 
     private static bool GetStyle(Control control, ControlStyles style) =>
diff --git a/OpenNest/Controls/HorizontalLine.cs b/OpenNest/Controls/HorizontalLine.cs
index c8d56386..0a8ef5e6 100644
--- a/OpenNest/Controls/HorizontalLine.cs
+++ b/OpenNest/Controls/HorizontalLine.cs
@@ -1,54 +1,12 @@
-using System;
 using System.Drawing;
-using System.Windows.Forms;
 
 namespace OpenNest.Controls
 {
-    public class HorizontalLine : Control
+    public class HorizontalLine : SeparatorLine
     {
-        private readonly Pen lightPen;
-        private readonly Pen darkPen;
+        protected override int Across => Height;
 
-        public HorizontalLine()
-        {
-            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
-            SetStyle(ControlStyles.Selectable, false);
-
-            lightPen = new Pen(ProfessionalColors.SeparatorLight);
-            darkPen = new Pen(ProfessionalColors.SeparatorDark);
-        }
-
-        protected override void Dispose(bool disposing)
-        {
-            try
-            {
-                if (disposing)
-                {
-                    lightPen.Dispose();
-                    darkPen.Dispose();
-                }
-            }
-            finally
-            {
-                base.Dispose(disposing);
-            }
-        }
-
-        protected override void OnResize(EventArgs e)
-        {
-            base.OnResize(e);
-            Invalidate();
-        }
-
-        protected override void OnPaint(PaintEventArgs e)
-        {
-            base.OnPaint(e);
-
-            float midpoint = Height * 0.5f;
-
-            e.Graphics.DrawLine(darkPen, 0, midpoint, Width, midpoint);
-            midpoint++;
-            e.Graphics.DrawLine(lightPen, 0, midpoint, Width, midpoint);
-        }
+        protected override void DrawLine(Graphics graphics, Pen pen, float position) =>
+            graphics.DrawLine(pen, 0, position, Width, position);
     }
 }
diff --git a/OpenNest/Controls/SeparatorLine.cs b/OpenNest/Controls/SeparatorLine.cs
new file mode 100644
index 00000000..88eee54e
--- /dev/null
+++ b/OpenNest/Controls/SeparatorLine.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace OpenNest.Controls
+{
+    /// <summary>An etched separator: a dark line at the middle with a light line beside it.</summary>
+    public abstract class SeparatorLine : Control
+    {
+        private readonly Pen lightPen;
+        private readonly Pen darkPen;
+
+        protected SeparatorLine()
+        {
+            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
+            SetStyle(ControlStyles.Selectable, false);
+
+            lightPen = new Pen(ProfessionalColors.SeparatorLight);
+            darkPen = new Pen(ProfessionalColors.SeparatorDark);
+        }
+
+        /// <summary>The control's size across the line: Height for a horizontal line.</summary>
+        protected abstract int Across { get; }
+
+        /// <summary>Draws the full-length line at <paramref name="position"/> across it.</summary>
+        protected abstract void DrawLine(Graphics graphics, Pen pen, float position);
+
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing)
+                {
+                    lightPen.Dispose();
+                    darkPen.Dispose();
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        protected override void OnResize(EventArgs e)
+        {
+            base.OnResize(e);
+            Invalidate();
+        }
+
+        protected override void OnPaint(PaintEventArgs e)
+        {
+            base.OnPaint(e);
+
+            float midpoint = Across * 0.5f;
+
+            DrawLine(e.Graphics, darkPen, midpoint);
+            midpoint++;
+            DrawLine(e.Graphics, lightPen, midpoint);
+        }
+    }
+}
diff --git a/OpenNest/Controls/VerticalLine.cs b/OpenNest/Controls/VerticalLine.cs
index a0c23a59..e87c88c6 100644
--- a/OpenNest/Controls/VerticalLine.cs
+++ b/OpenNest/Controls/VerticalLine.cs
@@ -1,54 +1,12 @@
-using System;
 using System.Drawing;
-using System.Windows.Forms;
 
 namespace OpenNest.Controls
 {
-    public class VerticalLine : Control
+    public class VerticalLine : SeparatorLine
     {
-        private readonly Pen lightPen;
-        private readonly Pen darkPen;
+        protected override int Across => Width;
 
-        public VerticalLine()
-        {
-            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
-            SetStyle(ControlStyles.Selectable, false);
-
-            lightPen = new Pen(ProfessionalColors.SeparatorLight);
-            darkPen = new Pen(ProfessionalColors.SeparatorDark);
-        }
-
-        protected override void Dispose(bool disposing)
-        {
-            try
-            {
-                if (disposing)
-                {
-                    lightPen.Dispose();
-                    darkPen.Dispose();
-                }
-            }
-            finally
-            {
-                base.Dispose(disposing);
-            }
-        }
-
-        protected override void OnResize(EventArgs e)
-        {
-            base.OnResize(e);
-            Invalidate();
-        }
-
-        protected override void OnPaint(PaintEventArgs e)
-        {
-            base.OnPaint(e);
-
-            float midpoint = Width * 0.5f;
-
-            e.Graphics.DrawLine(darkPen, midpoint, 0, midpoint, Height);
-            midpoint++;
-            e.Graphics.DrawLine(lightPen, midpoint, 0, midpoint, Height);
-        }
+        protected override void DrawLine(Graphics graphics, Pen pen, float position) =>
+            graphics.DrawLine(pen, position, 0, position, Height);
     }
 }