diff --git a/src/extract.zig b/src/extract.zig
index 57b87d7..1533d62 100644
--- a/src/extract.zig
+++ b/src/extract.zig
@@ -113,8 +113,7 @@ pub fn extractLevel(opt: Options) !void {
 
     for (autotiles) |autotile_opt, i| {
         if (autotile_opt) |autotile| {
-            const li = autotile.to_u4();
-            const tile = tileset.lookup[li];
+            const tile = tileset.find(autotile);
             map.tiles[i] = tile;
         }
     }
@@ -177,12 +176,11 @@ pub fn extractLevel(opt: Options) !void {
 
     for (autotiles) |autotile_opt, i| {
         if (autotile_opt) |autotile| {
-            const li = autotile.to_u4();
             const tile = switch (circuit_map[i]) {
-                .Conduit, .Source, .Join => opt.conduit.lookup[li],
-                .Switch_On => opt.switch_on.lookup[li],
-                .Switch_Off => opt.switch_off.lookup[li],
-                .Plug => opt.plug.lookup[li],
+                .Conduit, .Source, .Join => opt.conduit.find(autotile),
+                .Switch_On => opt.switch_on.find(autotile),
+                .Switch_Off => opt.switch_off.find(autotile),
+                .Plug => opt.plug.find(autotile),
                 .And => 60,
                 .Xor => 62,
                 else => 0,
diff --git a/src/rewrite.zig b/src/rewrite.zig
index 01a0163..4aa8c4c 100644
--- a/src/rewrite.zig
+++ b/src/rewrite.zig
@@ -44,7 +44,7 @@ pub fn start() !void {
         .level = level,
         .map = &map,
         .circuit = &circuit,
-        .tileset = world.AutoTileset{ .lookup = .{
+        .tileset = world.AutoTileset.initFull(&.{
             35, // Island
             51, // North
             52, // West
@@ -61,8 +61,8 @@ pub fn start() !void {
             37, // South-East-North
             22, // South-East-West
             0, // South-East-West-North
-        }},
-        .conduit = world.AutoTileset{ .lookup = .{
+        }),
+        .conduit = world.AutoTileset.initFull(&.{
             42, // Island
             58, // North
             59, // West
@@ -79,61 +79,23 @@ pub fn start() !void {
             75, // South-East-North
             72, // South-East-West
             43, // South-East-West-North
-        } },
-        .plug = world.AutoTileset{ .lookup = .{
-            02, // Island
+        }),
+        .plug = world.AutoTileset.initCardinal(&.{
             45, // North
             46, // West
-            02, // West-North
             47, // East
-            02, // East-North
-            02, // East-West
-            02, // East-West-North
             44, // South
-            02, // South-North
-            02, // South-West
-            02, // South-West-North
-            02, // South-East
-            02, // South-East-North
-            02, // South-East-West
-            02, // South-East-West-North
-        } },
-        .switch_off = world.AutoTileset{ .lookup = .{
-            02, // Island
-            02, // North
-            02, // West
-            02, // West-North
-            02, // East
-            02, // East-North
-            02, // East-West
-            02, // East-West-North
-            02, // South
+        }, 2),
+        .switch_off = world.AutoTileset.initSwitches(&.{
             32, // South-North
-            02, // South-West
             29, // South-West-North
-            02, // South-East
             31, // South-East-North
-            02, // South-East-West
-            02, // South-East-West-North
-        } },
-        .switch_on = world.AutoTileset{ .lookup = .{
-            02, // Island
-            02, // North
-            02, // West
-            02, // West-North
-            02, // East
-            02, // East-North
-            02, // East-West
-            02, // East-West-North
-            02, // South
+        }, 2),
+        .switch_on = world.AutoTileset.initSwitches(&.{
             48, // South-North
-            02, // South-West
             28, // South-West-North
-            02, // South-East
-            02, // South-East-North
             30, // South-East-West
-            02, // South-East-West-North
-        } },
+        }, 2),
     });
 }
 
diff --git a/src/world.zig b/src/world.zig
index e9543ee..c8d98bd 100644
--- a/src/world.zig
+++ b/src/world.zig
@@ -96,7 +96,7 @@ pub const Level = struct {
     tiles: []TileStore,
 
     pub fn init(header: LevelHeader, buf: []TileStore) Level {
-        return Level {
+        return Level{
             .world_x = header.world_x,
             .world_y = header.world_y,
             .width = header.width,
@@ -122,5 +122,58 @@ pub const AutoTile = packed struct {
 };
 
 pub const AutoTileset = struct {
-    lookup: [16]u8,
+    lookup: []const u8,
+    kind: enum {
+        Cardinal,
+        Switches,
+        Full,
+    },
+    default: u8,
+
+    pub fn initFull(table: []const u8) AutoTileset {
+        std.debug.assert(table.len == 16);
+        return AutoTileset{
+            .lookup = table,
+            .kind = .Full,
+            .default = 0,
+        };
+    }
+
+    pub fn initCardinal(table: []const u8, default: u8) AutoTileset {
+        std.debug.assert(table.len == 4);
+        return AutoTileset{
+            .lookup = table,
+            .kind = .Cardinal,
+            .default = default,
+        };
+    }
+
+    pub fn initSwitches(table: []const u8, default: u8) AutoTileset {
+        std.debug.assert(table.len == 3);
+        return AutoTileset{
+            .lookup = table,
+            .kind = .Switches,
+            .default = default,
+        };
+    }
+
+    pub fn find(tileset: AutoTileset, autotile: AutoTile) u8 {
+        const autoint = autotile.to_u4();
+        switch (tileset.kind) {
+            .Full => return tileset.lookup[autoint],
+            .Cardinal => switch (autoint) {
+                0b0001 => return tileset.lookup[0],
+                0b0010 => return tileset.lookup[1],
+                0b0100 => return tileset.lookup[2],
+                0b1000 => return tileset.lookup[3],
+                else => return tileset.default,
+            },
+            .Switches => switch (autoint) {
+                0b1001 => return tileset.lookup[0],
+                0b1011 => return tileset.lookup[1],
+                0b1101 => return tileset.lookup[2],
+                else => return tileset.default,
+            },
+        }
+    }
 };