diff --git a/public/index.html b/public/index.html
index f32ef3f..939d27f 100644
--- a/public/index.html
+++ b/public/index.html
@@ -17,7 +17,7 @@
   <script>
     "use strict";
     const cellSizePx = 55;
-    const gridSize = 14;
+    const gridSize = 15;
     const gapPx = 4;
     customElements.define('scroll-repeat', class extends HTMLElement {
       constructor() { super(); }
@@ -43,7 +43,7 @@
           const grid = document.querySelector(".grid");
           const maxDim = Math.max(this.offsetWidth, this.offsetHeight);
           const offsetWidth = this.offsetWidth;
-          const visualGridSizePx = cellSizePx * (gridSize + 1) + gapPx * gridSize;
+          const visualGridSizePx = cellSizePx * gridSize + gapPx * gridSize;
           // Zoom level that would fit one partial grid perfectly in the scroll-repeat
           const zoomToFit = maxDim / partialGridSizePx;
           // Zoom level that would fit the "visual" grid (with duplicated edges) perfectly in the scroll-repeat
diff --git a/public/main.css b/public/main.css
index 0759518..0c4b6d5 100644
--- a/public/main.css
+++ b/public/main.css
@@ -8,7 +8,7 @@
   --col-placed-tile: #fff;
   --col-cell: #2d2d2d;
   --col-success: #84ff7a;
-  --grid-size: 14;
+  --grid-size: 15;
   --grid-gap: 4px;
   --default-board-size: calc((var(--cell-size) + var(--grid-gap)) * (var(--grid-size) + 1));
   --tile-border-radius: 10px;
@@ -114,7 +114,7 @@ dialog > form {
   display: grid;
   grid-template-columns: auto auto auto;
   grid-template-rows: auto auto auto;
-  grid-gap: var(--grid-gap);
+  grid-gap: calc(var(--grid-gap) * 2);
 }
 
 .grid {
diff --git a/src/Checker.elm b/src/Checker.elm
index fb3aba2..74f53e5 100644
--- a/src/Checker.elm
+++ b/src/Checker.elm
@@ -32,7 +32,7 @@ type CheckerResult
 
 gridSize : Int
 gridSize =
-    14
+    15
 
 
 maxRackSize : Int
@@ -43,36 +43,37 @@ maxRackSize =
 multipliers : Array2D Multiplier
 multipliers =
     let
-        normalize n =
-            abs (n - gridSize // 2)
+        -- Repeat a tile in all four quadrants
+        tile ( x, y ) val =
+            [ ( ( x, y ), val )
+            , ( ( y, -x ), val )
+            , ( ( -x, -y ), val )
+            , ( ( -y, x ), val )
+            ]
 
         multDict =
-            Dict.fromList
-                [ ( ( 7, 7 ), Multiplier 1 3 )
-                , ( ( 7, 0 ), Multiplier 1 3 )
-                , ( ( 0, 7 ), Multiplier 1 3 )
-                , ( ( 7, 4 ), Multiplier 2 1 )
-                , ( ( 4, 7 ), Multiplier 2 1 )
-                , ( ( 2, 6 ), Multiplier 3 1 )
-                , ( ( 6, 2 ), Multiplier 3 1 )
-                , ( ( 1, 5 ), Multiplier 2 1 )
-                , ( ( 0, 4 ), Multiplier 2 1 )
-                , ( ( 4, 0 ), Multiplier 2 1 )
-                , ( ( 5, 1 ), Multiplier 2 1 )
-                , ( ( 6, 6 ), Multiplier 1 2 )
-                , ( ( 5, 5 ), Multiplier 1 2 )
-                , ( ( 4, 4 ), Multiplier 1 2 )
-                , ( ( 3, 3 ), Multiplier 1 2 )
-                , ( ( 2, 2 ), Multiplier 3 1 )
-                , ( ( 1, 1 ), Multiplier 2 1 )
-                , ( ( 0, 0 ), Multiplier 1 2 )
-                ]
+            Dict.fromList <|
+                ( ( 0, 0 ), Multiplier 1 2 )
+                    :: tile ( 6, 1 ) (Multiplier 1 2)
+                    ++ tile ( 3, 4 ) (Multiplier 1 2)
+                    ++ tile ( 2, 7 ) (Multiplier 1 2)
+                    ++ tile ( 5, 6 ) (Multiplier 1 3)
+                    ++ tile ( 4, 3 ) (Multiplier 1 3)
+                    ++ tile ( 2, 2 ) (Multiplier 3 1)
+                    ++ tile ( 7, 7 ) (Multiplier 3 1)
+                    ++ tile ( 5, 2 ) (Multiplier 3 1)
+                    ++ tile ( 7, 0 ) (Multiplier 3 1)
+                    ++ tile ( 7, 4 ) (Multiplier 2 1)
+                    ++ tile ( 1, 1 ) (Multiplier 2 1)
+                    ++ tile ( 6, 5 ) (Multiplier 2 1)
+                    ++ tile ( 4, 7 ) (Multiplier 2 1)
+                    ++ tile ( 3, 0 ) (Multiplier 2 1)
     in
     Array2D.initialize gridSize
         gridSize
         (\x y ->
             multDict
-                |> Dict.get ( normalize x, normalize y )
+                |> Dict.get ( x - gridSize // 2, y - gridSize // 2 )
                 |> Maybe.withDefault (Multiplier 1 1)
         )