diff --git a/AoC_2025.Tests/Day09Test.cs b/AoC_2025.Tests/Day09Test.cs
index bba1084..8ce4198 100644
--- a/AoC_2025.Tests/Day09Test.cs
+++ b/AoC_2025.Tests/Day09Test.cs
@@ -7,6 +7,7 @@ public class Day09Test
     private IPuzzleSolver<long> _sut;
     private static readonly string rootPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
     private readonly string TestInputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Test\day09.txt";
+    private readonly string Test2InputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Test\day09_2.txt";
     private readonly string ProdInputPath = @$"{rootPath}\AoC-PuzzleInputs\2025\Prod\day09.txt";
     
     public Day09Test()
@@ -37,6 +38,15 @@ public class Day09Test
         Assert.Equal(24, actual);
     }
     
+    [Fact]
+    public void Part02_Test2_equals_30()
+    {
+        // todo: color edges as right, left, up, down to only allow rectangles between right and left or up and down edges
+        var actual = _sut.SolvePart2(Test2InputPath);
+        
+        Assert.Equal(30, actual);
+    }
+    
     [Fact]
     public void Part02_Prod_equals_1568849600()
     {
diff --git a/AoC_2025/Day04.cs b/AoC_2025/Day04.cs
index 323a90c..568296c 100644
--- a/AoC_2025/Day04.cs
+++ b/AoC_2025/Day04.cs
@@ -55,13 +55,12 @@ public class Day04 : IPuzzleSolver<long>
     private HashSet<Coordinate> GetRollCoordinates(IEnumerable<string> paperrollGrid)
     {
         var coordinates = paperrollGrid
-            .Index()
-            .SelectMany(indexedLine => GetCoordinates(indexedLine.Item, indexedLine.Index))
+            .SelectMany((line, xIndex) => GetRollCoordinates(line, xIndex))
             .ToHashSet();
         return coordinates;
     }
 
-    private IEnumerable<Coordinate> GetCoordinates(string gridLine, int xIndex)
+    private IEnumerable<Coordinate> GetRollCoordinates(string gridLine, int xIndex)
     {
         var indexedCharacters = gridLine.Index();
         var validRolls = indexedCharacters.Where(tuple => tuple.Item == '@');
diff --git a/AoC_2025/Day09.cs b/AoC_2025/Day09.cs
index 5d3c543..4c44c60 100644
--- a/AoC_2025/Day09.cs
+++ b/AoC_2025/Day09.cs
@@ -64,7 +64,8 @@ public class Day09 : IPuzzleSolver<long>
 
     private bool IsRectangleInsideBorders(CoordinatePair[] borders, CoordinatePair rectangle)
     {
-        return !borders.Any(border => RectangleCrossesBorder(rectangle, border));
+        var bordersCrossed = borders.Any(border => RectangleCrossesBorder(rectangle, border));
+        return !bordersCrossed;
     }
 
     private CoordinatePair AsPair(Coordinate a, Coordinate b)