diff --git a/src/azul.rs b/src/azul.rs
index 6bab061..cc602c5 100644
--- a/src/azul.rs
+++ b/src/azul.rs
@@ -8,6 +8,7 @@ use rand::prelude::*;
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
 struct GameState {
+    n_players: usize,
     current_player: usize,
     bag: TileSet,
     lid: TileSet,
@@ -44,6 +45,7 @@ impl GameState {
         }
 
         let game = GameState {
+            n_players,
             current_player: 0,
             bag: TileSet {
                 blue: 20,
@@ -53,7 +55,7 @@ impl GameState {
                 white: 20,
             },
             lid: TileSet::default(),
-            factories: factories,
+            factories,
             market: TileSetWithStart {
                 start: 1,
                 blue: 0,
@@ -62,7 +64,7 @@ impl GameState {
                 black: 0,
                 white: 0,
             },
-            players: players,
+            players,
         };
 
         Ok(game)
@@ -126,7 +128,7 @@ impl GameState {
                     player.wall[row][index] = true;
                     player.points += player.connected(row, index);
 
-                    self.lid.add_color(color, row)?;
+                    self.lid.add_color(color, row as isize)?;
                     player.pattern_lines[row] = PatternLine::default()
                 }
             }
@@ -154,6 +156,142 @@ impl GameState {
 
         Ok(())
     }
+
+    /// Does a move according to the policy defined in the move
+    fn do_move(&mut self, game_move: GameMove) -> Result<(), MoveErr> {
+        match game_move.policy {
+            Policy::Strict => self.do_move_strict(game_move),
+            Policy::Loose => self.do_move_loose(game_move),
+        }
+    }
+
+    /// Does a move, if the move is placed where it can't fit, places it on the floor
+    fn do_move_loose(&mut self, game_move: GameMove) -> Result<(), MoveErr> {
+        match self.do_move_strict(game_move) {
+            Ok(()) => Ok(()),
+            Err(MoveErr::Dst(_)) => {
+                let mut new_game_move = game_move.clone();
+                new_game_move.destination = Destination::Floor;
+                self.do_move_strict(new_game_move)
+            }
+            e => e,
+        }
+    }
+
+    /// Does a move, errors out if the move is weird in any way
+    fn do_move_strict(&mut self, game_move: GameMove) -> Result<(), MoveErr> {
+        let current_player = self.current_player;
+
+        if current_player != game_move.player {
+            return Err(MoveErr::Player("Not this player's turn"));
+        }
+
+        // let player = &mut self.players[current_player];
+
+        let color = game_move.color;
+        let src = game_move.source;
+        let dst = game_move.destination;
+
+        match (color, src, dst) {
+            (Color::Start, _, _) => {
+                return Err(MoveErr::Color("You can't take the start tile specifically"))
+            }
+            (c, s, _) if self.get_color(s, c) == 0 => {
+                return Err(MoveErr::Color("Source does not contain that color"))
+            }
+            (_, Source::Factory(f), _) if f >= self.factories.len() => {
+                return Err(MoveErr::Src("Not a valid factory"))
+            }
+            (_, _, Destination::PatternLine(l))
+                if self.players[current_player].pattern_lines[l].number > l + 1 =>
+            {
+                return Err(MoveErr::Dst("That PatternLine is full!"))
+            }
+            (c, _, Destination::PatternLine(l))
+                if self.players[current_player].pattern_lines[l].color != Some(c)
+                    && !self.players[current_player].pattern_lines[l]
+                        .color
+                        .is_none() =>
+            {
+                return Err(MoveErr::Dst(
+                    "That pattern line already contains tiles of a different color!",
+                ))
+            }
+            (c, _, Destination::PatternLine(l))
+                if self.players[current_player].wall[l][Player::get_wall_index(l, c).unwrap()]
+                    == true =>
+            {
+                return Err(MoveErr::Dst(
+                    "That pattern line and color is already filled on the wall",
+                ))
+            }
+            (c, s, Destination::PatternLine(p)) => {
+                let amount = self.take_tiles(s, c);
+
+                let pattern_line = &mut self.players[current_player].pattern_lines[p];
+
+                let remaining_capacity = p + 1 - pattern_line.len();
+                let to_line = usize::min(amount, remaining_capacity);
+                let to_floor = amount - to_line;
+
+                pattern_line.number += to_line;
+                self.players[current_player]
+                    .floor
+                    .add_color(c, to_floor as isize)
+                    .map_err(|e| MoveErr::Other(e))?;
+            }
+            (c, s, Destination::Floor) => {
+                let amount = self.take_tiles(s, c);
+                self.players[self.current_player]
+                    .floor
+                    .add_color(c, amount as isize)
+                    .map_err(|e| MoveErr::Other(e))?;
+            }
+        };
+
+        self.current_player = current_player + 1 % self.n_players;
+        Ok(())
+    }
+
+    /// Gets how many tiles of a given color is in a source
+    fn get_color(&self, src: Source, color: Color) -> usize {
+        match src {
+            Source::Market => self.market.get_color(color),
+            Source::Factory(f) => self.factories[f].get_color(color),
+        }
+    }
+
+    /// Takes tiles from a source and causes side-effects
+    fn take_tiles(&mut self, src: Source, color: Color) -> usize {
+        let amount = self.get_color(src, color);
+        let player = &mut self.players[self.current_player];
+
+        // Sideffects
+        match src {
+            Source::Market => {
+                if self.market.start == 1 {
+                    self.market.start -= 1;
+                    player.floor.start += 1;
+                }
+            }
+            Source::Factory(f) => {
+                let factory = &mut self.factories[f];
+                factory.add_color(color, -(amount as isize)).unwrap();
+                self.market += *factory;
+                factory.clear();
+            }
+        };
+
+        return amount;
+    }
+}
+
+enum MoveErr {
+    Player(&'static str),
+    Color(&'static str),
+    Src(&'static str),
+    Dst(&'static str),
+    Other(&'static str),
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone, Default, Copy)]
@@ -173,18 +311,43 @@ impl TileSet {
         self.len() == 0
     }
 
-    fn add_color(&mut self, color: Color, n: usize) -> Result<(), &'static str> {
+    fn add_color(&mut self, color: Color, n: isize) -> Result<(), &'static str> {
         match color {
-            Color::Blue => self.blue += n,
-            Color::Yellow => self.yellow += n,
-            Color::Red => self.red += n,
-            Color::Black => self.black += n,
-            Color::White => self.white += n,
+            Color::Blue => {
+                self.blue = usize::checked_add_signed(self.blue, n).ok_or("would overflow!")?
+            }
+            Color::Yellow => {
+                self.blue = usize::checked_add_signed(self.yellow, n).ok_or("would overflow")?
+            }
+            Color::Red => {
+                self.blue = usize::checked_add_signed(self.red, n).ok_or("would overflow")?
+            }
+            Color::Black => {
+                self.blue = usize::checked_add_signed(self.black, n).ok_or("would overflow")?
+            }
+            Color::White => {
+                self.blue = usize::checked_add_signed(self.white, n).ok_or("would overflow")?
+            }
             Color::Start => return Err("tried to add Start tiles to TileSet"),
         }
 
         Ok(())
     }
+
+    fn get_color(&self, color: Color) -> usize {
+        match color {
+            Color::Start => 0,
+            Color::Blue => self.blue,
+            Color::Yellow => self.yellow,
+            Color::Red => self.red,
+            Color::Black => self.white,
+            Color::White => self.black,
+        }
+    }
+
+    fn clear(&mut self) {
+        *self = Self::default();
+    }
 }
 
 impl Add for TileSet {
@@ -242,6 +405,91 @@ impl TileSetWithStart {
     fn is_empty(&self) -> bool {
         self.len() == 0
     }
+    fn get_color(&self, color: Color) -> usize {
+        match color {
+            Color::Start => self.start,
+            Color::Blue => self.blue,
+            Color::Yellow => self.yellow,
+            Color::Red => self.red,
+            Color::Black => self.white,
+            Color::White => self.black,
+        }
+    }
+
+    fn add_color(&mut self, color: Color, n: isize) -> Result<(), &'static str> {
+        match color {
+            Color::Blue => {
+                self.blue = usize::checked_add_signed(self.blue, n).ok_or("would overflow!")?
+            }
+            Color::Yellow => {
+                self.blue = usize::checked_add_signed(self.yellow, n).ok_or("would overflow")?
+            }
+            Color::Red => {
+                self.blue = usize::checked_add_signed(self.red, n).ok_or("would overflow")?
+            }
+            Color::Black => {
+                self.blue = usize::checked_add_signed(self.black, n).ok_or("would overflow")?
+            }
+            Color::White => {
+                self.blue = usize::checked_add_signed(self.white, n).ok_or("would overflow")?
+            }
+            Color::Start if n == 1 && self.start == 0 => {
+                self.start = usize::checked_add_signed(self.white, n).ok_or("would overflow")?
+            }
+            Color::Start => return Err("Tried to add more than 1 start tile to TileSet"),
+        }
+
+        Ok(())
+    }
+}
+
+impl Add for TileSetWithStart {
+    type Output = Self;
+
+    fn add(self, other: Self) -> Self {
+        Self {
+            start: self.start + other.start,
+            blue: self.blue + other.blue,
+            yellow: self.yellow + other.yellow,
+            red: self.red + other.red,
+            black: self.black + other.black,
+            white: self.white + other.white,
+        }
+    }
+}
+
+impl Add<TileSet> for TileSetWithStart {
+    type Output = Self;
+
+    fn add(self, other: TileSet) -> Self {
+        Self {
+            start: self.start,
+            blue: self.blue + other.blue,
+            yellow: self.yellow + other.yellow,
+            red: self.red + other.red,
+            black: self.black + other.black,
+            white: self.white + other.white,
+        }
+    }
+}
+
+impl AddAssign<TileSet> for TileSetWithStart {
+    fn add_assign(&mut self, other: TileSet) {
+        *self = *self + other
+    }
+}
+
+impl From<TileSet> for TileSetWithStart {
+    fn from(value: TileSet) -> Self {
+        TileSetWithStart {
+            start: 0,
+            blue: value.blue,
+            yellow: value.yellow,
+            red: value.red,
+            black: value.black,
+            white: value.white,
+        }
+    }
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone, Default)]
@@ -396,7 +644,7 @@ impl PatternLine {
     }
 }
 
-#[derive(Debug, Serialize, Deserialize, Clone, Copy)]
+#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq, Eq)]
 enum Color {
     Start,
     Blue,
@@ -453,10 +701,41 @@ impl Iterator for ColorIter {
 type Row = [bool; 5];
 type Wall = [Row; 5];
 
+#[derive(Serialize, Deserialize, Clone, Copy)]
 struct GameMove {
-    player: u8,
-    market: bool,
-    factory: u8,
-    color: Color,
-    pattern_line: usize,
+    player: usize,            // Safeguard to check that the bot knows which player it is
+    policy: Policy,           // What policy to run moves under, so bots can do less error-handling
+    color: Color,             // What color to select
+    source: Source,           // What source to move the tiles from
+    destination: Destination, // Where to place the tiles
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy)]
+#[serde(untagged)]
+enum Policy {
+    /// Anything weird will return an error
+    #[serde(rename = "strict")]
+    Strict,
+    #[serde(rename = "loose")]
+    /// If you place tiles wrongly, they will fall on the floor, anything else will return an error
+    Loose,
+    // Anything weird will instead play a random move
+    // #[serde(rename = "random")]
+    // Random,
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy)]
+#[serde(untagged)]
+enum Source {
+    #[serde(rename = "market")]
+    Market,
+    Factory(usize),
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy)]
+#[serde(untagged)]
+enum Destination {
+    PatternLine(usize),
+    #[serde(rename = "floor")]
+    Floor,
 }