diff --git a/.gitignore b/.gitignore
index 3c2df47..541a8dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 /target
 /index.html
 /Cargo.lock
-/style.css
+/includes/style.css
 /examples/
diff --git a/build.sh b/build.sh
index 4b778c3..ac2bd52 100755
--- a/build.sh
+++ b/build.sh
@@ -1,5 +1,5 @@
 #! /usr/bin/env bash
 
 pug index.pug
-lessc style.less style.css
+lessc includes/style.less includes/style.css
 wasm-pack build --target web
diff --git a/background.png b/includes/background.png
similarity index 100%
rename from background.png
rename to includes/background.png
diff --git a/style.less b/includes/style.less
similarity index 100%
rename from style.less
rename to includes/style.less
diff --git a/index.pug b/index.pug
index eafaf8e..cd850d3 100644
--- a/index.pug
+++ b/index.pug
@@ -3,7 +3,7 @@ html(lang="en-gb")
     head
         meta(charset="utf-8")
         title tilesy
-        link(rel="stylesheet" href="style.css")
+        link(rel="stylesheet" href="includes/style.css")
     body
         h1
             span.background tilesy
diff --git a/script.js b/script.js
index 3a6080b..09486c4 100644
--- a/script.js
+++ b/script.js
@@ -53,9 +53,13 @@ async function run() {
     const buttonImportGame       = el("import");
     const buttonLoadGame         = el("load");
     const buttonNewGame          = el("new");
+    const buttonReset            = el("reset");
+    const checkboxInvertTiles    = el("invert");
+    const checkboxFlipTiles      = el("flip");
+    const checkboxMirrorTiles    = el("mirror");
+    const checkboxRotateTiles    = el("rotate");
     const inputPrefix            = el("prefix");
     const imagePreview           = el("preview");
-    const resetButton            = el("reset");
     const spanTileNamePreview    = el("tile-name-preview")
     const textareaGameDataInput  = el("game-data");
     const textareaGameDataOutput = el("output");
@@ -135,7 +139,15 @@ async function run() {
         let gameData = textareaGameDataInput.value;
         let prefix   = inputPrefix.value;
 
-        textareaGameDataOutput.value = add_tiles(gameData, image, prefix);
+        textareaGameDataOutput.value = add_tiles(
+            gameData,
+            image,
+            prefix,
+            checkboxInvertTiles.checked,
+            checkboxFlipTiles.checked,
+            checkboxMirrorTiles.checked,
+            checkboxRotateTiles.checked
+        );
     }
 
     buttonImportGame.addEventListener("click",    addTiles);
@@ -162,8 +174,8 @@ async function run() {
         imagePreview.removeAttribute("src");
     }
 
-    resetButton.addEventListener("click",    reset);
-    resetButton.addEventListener("touchend", reset);
+    buttonReset.addEventListener("click",    reset);
+    buttonReset.addEventListener("touchend", reset);
 }
 
 run();
diff --git a/src/lib.rs b/src/lib.rs
index dd913fc..fe2fd21 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,7 +22,15 @@ fn tile_name(prefix: &str, index: &u32) -> Option<String> {
 /// image is a base64-encoded string
 /// prefix will be ignored if empty
 #[wasm_bindgen]
-pub fn add_tiles(game_data: String, image: String, prefix: String) -> String {
+pub fn add_tiles(
+    game_data: String,
+    image: String,
+    prefix: String,
+    invert: bool,
+    flip: bool,
+    mirror: bool,
+    rotate: bool
+) -> String {
     let game = Game::from(game_data);
     if game.is_err() {
         return format!("Couldn't parse game data");
@@ -43,10 +51,10 @@ pub fn add_tiles(game_data: String, image: String, prefix: String) -> String {
     }
     let image = image.unwrap();
 
-    let width  = image.width();
-    let height = image.height();
-    let columns = (width  as f64 / 8.).floor() as u32;
-    let rows    = (height as f64 / 8.).floor() as u32;
+    let width   = image.width();
+    let height  = image.height();
+    let columns = (width  as f64 / SD as f64).floor() as u32;
+    let rows    = (height as f64 / SD as f64).floor() as u32;
 
     let mut tile_index = 1;
 
@@ -73,10 +81,75 @@ pub fn add_tiles(game_data: String, image: String, prefix: String) -> String {
             };
 
             if !game.tiles.contains(&tile) {
-                game.add_tile(tile);
+                game.add_tile(tile.clone());
 
                 tile_index += 1;
             }
+
+            if invert {
+                let mut inverted = tile.clone();
+                inverted.invert();
+
+                if inverted.name.is_some() {
+                    inverted.name = Some(format!("{} inverted", inverted.name.unwrap()));
+                }
+
+                if !game.tiles.contains(&inverted) {
+                    game.add_tile(inverted);
+
+                    tile_index += 1;
+                }
+            }
+
+            if flip {
+                let mut flipped = tile.clone();
+                flipped.flip();
+
+                if flipped.name.is_some() {
+                    flipped.name = Some(format!("{} flipped", flipped.name.unwrap()));
+                }
+
+                if !game.tiles.contains(&flipped) {
+                    game.add_tile(flipped);
+
+                    tile_index += 1;
+                }
+            }
+
+            if mirror {
+                let mut mirrored = tile.clone();
+                mirrored.mirror();
+
+                if mirrored.name.is_some() {
+                    mirrored.name = Some(format!("{} mirrored", mirrored.name.unwrap()));
+                }
+
+                if !game.tiles.contains(&mirrored) {
+                    game.add_tile(mirrored);
+
+                    tile_index += 1;
+                }
+            }
+
+            if rotate {
+                for i in 1..4 {
+                    let mut rotated = tile.clone();
+
+                    for _ in 0..i {
+                        rotated.rotate();
+                    }
+
+                    if rotated.name.is_some() {
+                        rotated.name = Some(format!("{} {}°", rotated.name.unwrap(), i * 90));
+                    }
+
+                    if !game.tiles.contains(&rotated) {
+                        game.add_tile(rotated);
+
+                        tile_index += 1;
+                    }
+                }
+            }
         }
     }
 
@@ -92,7 +165,17 @@ mod test {
     fn example() {
         let game_data = bitsy_parser::mock::game_default().to_string();
         let image = include_str!("test-resources/test.png.base64").to_string();
-        let output = add_tiles(game_data, image, "".to_string());
+
+        let output = add_tiles(
+            game_data,
+            image,
+            "".to_string(),
+            false,
+            false,
+            false,
+            false
+        );
+
         let expected = include_str!("test-resources/expected.bitsy");
         assert_eq!(output, expected);
     }