diff --git a/src/main.rs b/src/main.rs
index e6b9e69..01d087d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -484,19 +484,26 @@ fn test_image_to_string() {
     assert_eq!(output, expected);
 }
 
-fn animation_frames_to_string(animation_frames: Vec<Image>) -> String {
-    let mut string = String::new();
-    let last_frame = animation_frames.len() - 1;
+pub trait AnimationFrames {
+    fn to_string(&self) -> String;
+}
 
-    for (i, frame) in animation_frames.into_iter().enumerate() {
-        string.push_str(&frame.to_string());
+impl AnimationFrames for Vec<Image> {
+    #[inline]
+    fn to_string(&self) -> String {
+        let mut string = String::new();
+        let last_frame = self.len() - 1;
 
-        if i < last_frame {
-            string.push_str(&"\n>\n".to_string());
+        for (i, frame) in self.into_iter().enumerate() {
+            string.push_str(&frame.to_string());
+
+            if i < last_frame {
+                string.push_str(&"\n>\n".to_string());
+            }
         }
-    }
 
-    string
+        string
+    }
 }
 
 fn tile_from_string(string: String) -> Tile {
@@ -551,19 +558,22 @@ fn test_tile_from_string() {
     assert_eq!(output, expected);
 }
 
-fn tile_to_string(tile: Tile) -> String {
-    format!(
-        "TIL {}\n{}{}{}",
-        tile.id,
-        animation_frames_to_string(tile.animation_frames),
-        if tile.name.is_some() {format!("\nNAME {}", tile.name.unwrap())} else {"".to_string()},
-        if tile.wall {"\nWAL true"} else {""}
-    )
+impl ToString for Tile {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!(
+            "TIL {}\n{}{}{}",
+            self.id,
+            self.animation_frames.to_string(),
+            if self.name.as_ref().is_some() { format!("\nNAME {}", self.name.as_ref().unwrap())} else {"".to_string() },
+            if self.wall {"\nWAL true"} else {""}
+        )
+    }
 }
 
 #[test]
 fn test_tile_to_string() {
-    let output = tile_to_string(Tile {
+    let output = Tile {
         id: "7a".to_string(),
         name: Some("chequers".to_string()),
         wall: false,
@@ -571,7 +581,7 @@ fn test_tile_to_string() {
             example_image_chequers_1(),
             example_image_chequers_2(),
         ]
-    });
+    }.to_string();
 
     let expected = include_str!("../test/resources/tile-chequers").to_string();
 
@@ -756,20 +766,21 @@ fn test_avatar_from_string() {
     assert_eq!(output, expected);
 }
 
-fn avatar_to_string(avatar: Avatar) -> String {
-    format!(
-        "SPR A\n{}\nPOS {} {}",
-        animation_frames_to_string(avatar.animation_frames),
-        avatar.room,
-        avatar.position.to_string()
-    )
+impl ToString for Avatar {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!(
+            "SPR A\n{}\nPOS {} {}",
+            self.animation_frames.to_string(),
+            self.room,
+            self.position.to_string()
+        )
+    }
 }
 
 #[test]
 fn test_avatar_to_string() {
-    let output = avatar_to_string(example_avatar());
-    let expected = include_str!("../test/resources/avatar");
-    assert_eq!(output, expected);
+    assert_eq!(example_avatar().to_string(), include_str!("../test/resources/avatar"));
 }
 
 fn sprite_from_string(string: String) -> Sprite {
@@ -822,24 +833,24 @@ fn test_sprite_from_string() {
     assert_eq!(output, expected);
 }
 
-fn sprite_to_string(sprite: Sprite) -> String {
-    format!(
-        "SPR {}\n{}{}{}\nPOS {} {}",
-        sprite.id,
-        animation_frames_to_string(sprite.animation_frames),
-        if sprite.name.is_some() {format!("\nNAME {}", sprite.name.unwrap())} else {"".to_string()},
-        if sprite.dialogue.is_some() {format!("\nDLG {}", sprite.dialogue.unwrap())} else {"".to_string()},
-        sprite.room,
-        sprite.position.to_string(),
-    )
+impl ToString for Sprite {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!(
+            "SPR {}\n{}{}{}\nPOS {} {}",
+            self.id,
+            self.animation_frames.to_string(),
+            if self.name.as_ref().is_some() { format!("\nNAME {}", self.name.as_ref().unwrap()) } else { "".to_string() },
+            if self.dialogue.as_ref().is_some() { format!("\nDLG {}", self.dialogue.as_ref().unwrap()) } else { "".to_string() },
+            self.room,
+            self.position.to_string(),
+        )
+    }
 }
 
 #[test]
 fn test_sprite_to_string() {
-    let output = sprite_to_string(example_sprite());
-    let expected = include_str!("../test/resources/sprite").to_string();
-    
-    assert_eq!(output, expected);
+    assert_eq!(example_sprite().to_string(), include_str!("../test/resources/sprite").to_string());
 }
 
 fn item_from_string(string: String) -> Item {
@@ -882,21 +893,23 @@ fn test_item_from_string() {
     assert_eq!(output, expected);
 }
 
-fn item_to_string(item: Item) -> String {
-    format!(
-        "ITM {}\n{}{}{}", 
-        item.id, 
-        animation_frames_to_string(item.animation_frames),
-        if item.name.is_some() {format!("\nNAME {}", item.name.unwrap())} else {"".to_string()},
-        if item.dialogue.is_some() {format!("\nDLG {}", item.dialogue.unwrap())} else {"".to_string()},
-    )
+impl ToString for Item {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!(
+            "ITM {}\n{}{}{}",
+            self.id,
+            self.animation_frames.to_string(),
+            if self.name.is_some() { format!("\nNAME {}", self.name.as_ref().unwrap()) } else { "".to_string() },
+            if self.dialogue.is_some() { format!("\nDLG {}", self.dialogue.as_ref().unwrap()) } else { "".to_string() },
+        )
+    }
 }
 
 #[test]
 fn test_item_to_string() {
-    let output = item_to_string(example_item());
+    let output = example_item().to_string();
     let expected = include_str!("../test/resources/item").to_string();
-    
     assert_eq!(output, expected);
 }
 
@@ -917,14 +930,16 @@ fn test_exit_from_string() {
     );
 }
 
-fn exit_to_string(exit: Exit) -> String {
-    format!("{} {}", exit.room, exit.position.to_string())
+impl ToString for Exit {
+    fn to_string(&self) -> String {
+        format!("{} {}", self.room, self.position.to_string())
+    }
 }
 
 #[test]
 fn test_exit_to_string() {
     assert_eq!(
-        exit_to_string(Exit { room: "8".to_string(), position: Position { x: 5, y: 6 } }),
+        Exit { room: "8".to_string(), position: Position { x: 5, y: 6 } }.to_string(),
         "8 5,6".to_string()
     );
 }
@@ -949,19 +964,20 @@ fn test_ending_from_string() {
     );
 }
 
-fn ending_to_string(ending: Ending) -> String {
-    format!("END {}\n{}", ending.id, ending.dialogue)
+impl ToString for Ending {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!("END {}\n{}", self.id, self.dialogue)
+    }
 }
 
 #[test]
 fn test_ending_to_string() {
     assert_eq!(
-        ending_to_string(
-            Ending {
-                id: "7".to_string(),
-                dialogue: "This is another long ending. So long, farewell, etc.".to_string()
-            }
-        ),
+        Ending {
+            id: "7".to_string(),
+            dialogue: "This is another long ending. So long, farewell, etc.".to_string()
+        }.to_string(),
         "END 7\nThis is another long ending. So long, farewell, etc.".to_string()
     );
 }
@@ -1016,17 +1032,17 @@ fn test_variable_from_string() {
     );
 }
 
-fn variable_to_string(variable: Variable) -> String {
-    format!("VAR {}\n{}", variable.id, variable.initial_value)
+impl ToString for Variable {
+    #[inline]
+    fn to_string(&self) -> String {
+        format!("VAR {}\n{}", self.id, self.initial_value)
+    }
 }
 
 #[test]
 fn test_variable_to_string() {
-    let output = variable_to_string(
-        Variable { id: "c".to_string(), initial_value: "57".to_string() }
-    );
+    let output = Variable { id: "c".to_string(), initial_value: "57".to_string() }.to_string();
     let expected = "VAR c\n57".to_string();
-
     assert_eq!(output, expected);
 }
 
@@ -1098,59 +1114,61 @@ fn test_room_from_string() {
     assert_eq!(output, expected);
 }
 
-fn room_to_string(room: Room) -> String {
-    let mut tiles = String::new();
-    let mut items = String::new();
-    let mut exits = String::new();
-    let mut endings = String::new();
+impl ToString for Room {
+    fn to_string(&self) -> String {
+        let mut tiles = String::new();
+        let mut items = String::new();
+        let mut exits = String::new();
+        let mut endings = String::new();
 
-    let sqrt = (room.tiles.len() as f64).sqrt() as usize; // 8 for SD, 16 for HD
-    for line in room.tiles.chunks(sqrt) {
-        for tile in line {
-            tiles.push_str(&format!("{},", tile));
+        let sqrt = (self.tiles.len() as f64).sqrt() as usize; // 8 for SD, 16 for HD
+        for line in self.tiles.chunks(sqrt) {
+            for tile in line {
+                tiles.push_str(&format!("{},", tile));
+            }
+            tiles.pop(); // remove trailing comma
+            tiles.push_str("\n");
         }
-        tiles.pop(); // remove trailing comma
-        tiles.push_str("\n");
-    }
-    tiles.pop(); // remove trailing newline
+        tiles.pop(); // remove trailing newline
 
-    for instance in room.items {
-        items.push_str(
-            &format!("\nITM {} {}", instance.id, instance.position.to_string())
-        );
-    }
+        for instance in &self.items {
+            items.push_str(
+                &format!("\nITM {} {}", instance.id, instance.position.to_string())
+            );
+        }
 
-    for instance in room.exits {
-        exits.push_str(
-            &format!(
-                "\nEXT {} {}",
-                instance.position.to_string(),
-                exit_to_string(instance.exit)
-            )
-        );
-    }
+        for instance in &self.exits {
+            exits.push_str(
+                &format!(
+                    "\nEXT {} {}",
+                    instance.position.to_string(),
+                    instance.exit.to_string(),
+                )
+            );
+        }
 
-    for instance in room.endings {
-        endings.push_str(
-            &format!("\nEND {} {}", instance.id, instance.position.to_string())
-        );
-    }
+        for instance in &self.endings {
+            endings.push_str(
+                &format!("\nEND {} {}", instance.id, instance.position.to_string())
+            );
+        }
 
-    format!(
-        "ROOM {}\n{}{}{}{}{}\nPAL {}",
-        room.id,
-        tiles,
-        if room.name.is_some() {format!("\nNAME {}", room.name.unwrap())} else {"".to_string()},
-        items,
-        exits,
-        endings,
-        room.palette
-    )
+        format!(
+            "ROOM {}\n{}{}{}{}{}\nPAL {}",
+            self.id,
+            tiles,
+            if self.name.as_ref().is_some() { format!("\nNAME {}", self.name.as_ref().unwrap()) } else { "".to_string() },
+            items,
+            exits,
+            endings,
+            self.palette
+        )
+    }
 }
 
 #[test]
 fn test_room_to_string() {
-    assert_eq!(room_to_string(example_room()), example_room_string());
+    assert_eq!(example_room().to_string(), example_room_string());
 }
 
 fn game_from_string(string: String ) -> Game {
@@ -1162,7 +1180,6 @@ fn game_from_string(string: String ) -> Game {
     let main_split: Vec<&str> = string.split("\n\nDLG").collect();
     let main = main_split[0].to_string();
     let mut dialogues_endings_variables: String = main_split[1..].join("\n\nDLG");
-    // todo handle dialogues_endings_variables
 
     let variable_segments = dialogues_endings_variables.clone();
     let variable_segments: Vec<&str> = variable_segments.split("\n\nVAR").collect();
@@ -1188,7 +1205,6 @@ fn game_from_string(string: String ) -> Game {
         }
     }
 
-
     let dialogue_segments = format!("\n\nDLG {}", dialogues_endings_variables.trim());
     let dialogue_segments: Vec<&str> = dialogue_segments.split("\n\nDLG").collect();
     for segment in dialogue_segments[1..].to_owned() {
@@ -1259,57 +1275,60 @@ fn test_game_from_string() {
     assert_eq!(output, expected);
 }
 
-fn game_to_string(game: Game) -> String {
-    let mut segments : Vec<String> = Vec::new();
+impl ToString for Game {
+    #[inline]
+    fn to_string(&self) -> String {
+        let mut segments: Vec<String> = Vec::new();
 
-    // todo refactor
+        // todo refactor
 
-    for palette in game.palettes {
-        segments.push(palette.to_string());
+        for palette in &self.palettes {
+            segments.push(palette.to_string());
+        }
+
+        for room in &self.rooms {
+            segments.push(room.to_string());
+        }
+
+        for tile in &self.tiles {
+            segments.push(tile.to_string());
+        }
+
+        segments.push(self.avatar.to_string());
+
+        for sprite in &self.sprites {
+            segments.push(sprite.to_string());
+        }
+
+        for item in &self.items {
+            segments.push(item.to_string());
+        }
+
+        for dialogue in &self.dialogues {
+            segments.push(dialogue.to_string());
+        }
+
+        for ending in &self.endings {
+            segments.push(ending.to_string());
+        }
+
+        for variable in &self.variables {
+            segments.push(variable.to_string());
+        }
+
+        format!(
+            "{}\n\n# BITSY VERSION {}\n\n! ROOM_FORMAT {}\n\n{}\n\n",
+            &self.name,
+            &self.version,
+            &self.room_format,
+            segments.join("\n\n"),
+        )
     }
-
-    for room in game.rooms {
-        segments.push(room_to_string(room));
-    }
-
-    for tile in game.tiles {
-        segments.push(tile_to_string(tile));
-    }
-
-    segments.push(avatar_to_string(game.avatar));
-
-    for sprite in game.sprites {
-        segments.push(sprite_to_string(sprite));
-    }
-
-    for item in game.items {
-        segments.push(item_to_string(item));
-    }
-
-    for dialogue in game.dialogues {
-        segments.push(dialogue.to_string());
-    }
-
-    for ending in game.endings {
-        segments.push(ending_to_string(ending));
-    }
-
-    for variable in game.variables {
-        segments.push(variable_to_string(variable));
-    }
-
-    format!(
-        "{}\n\n# BITSY VERSION {}\n\n! ROOM_FORMAT {}\n\n{}\n\n",
-        game.name,
-        game.version,
-        game.room_format,
-        segments.join("\n\n"),
-    )
 }
 
 #[test]
 fn test_game_to_string() {
-    let output = game_to_string(example_game_default());
+    let output = example_game_default().to_string();
     let expected = include_str!["../test/resources/default.bitsy"].to_string();
     assert_eq!(output, expected);
 }