diff --git a/glloyd_and_dbetteridge/.idea/.gitignore b/glloyd_and_dbetteridge/.idea/.gitignore
new file mode 100644
index 0000000..13566b8
--- /dev/null
+++ b/glloyd_and_dbetteridge/.idea/.gitignore
@@ -0,0 +1,8 @@
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+/workspace.xml
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diff --git a/glloyd_and_dbetteridge/.idea/glloyd_and_dbetteridge.iml b/glloyd_and_dbetteridge/.idea/glloyd_and_dbetteridge.iml
new file mode 100644
index 0000000..cf84ae4
--- /dev/null
+++ b/glloyd_and_dbetteridge/.idea/glloyd_and_dbetteridge.iml
@@ -0,0 +1,11 @@
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diff --git a/glloyd_and_dbetteridge/.idea/modules.xml b/glloyd_and_dbetteridge/.idea/modules.xml
new file mode 100644
index 0000000..c7d89c9
--- /dev/null
+++ b/glloyd_and_dbetteridge/.idea/modules.xml
@@ -0,0 +1,8 @@
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\ No newline at end of file
diff --git a/glloyd_and_dbetteridge/.idea/vcs.xml b/glloyd_and_dbetteridge/.idea/vcs.xml
new file mode 100644
index 0000000..6c0b863
--- /dev/null
+++ b/glloyd_and_dbetteridge/.idea/vcs.xml
@@ -0,0 +1,6 @@
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new file mode 100644
index 0000000..113946d
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+++ b/glloyd_and_dbetteridge/Cargo.lock
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diff --git a/glloyd_and_dbetteridge/Cargo.toml b/glloyd_and_dbetteridge/Cargo.toml
new file mode 100644
index 0000000..e446a79
--- /dev/null
+++ b/glloyd_and_dbetteridge/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "tennis"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+name = "tennis"
+
+[dependencies]
+rstest = "0.25.0"
diff --git a/glloyd_and_dbetteridge/src/lib.rs b/glloyd_and_dbetteridge/src/lib.rs
new file mode 100644
index 0000000..87b3db6
--- /dev/null
+++ b/glloyd_and_dbetteridge/src/lib.rs
@@ -0,0 +1,143 @@
+use std::fmt::Display;
+
+#[derive(PartialEq, Copy, Clone)]
+pub enum PlayerScore {
+    Love,
+    Fifteen,
+    Thirty,
+    Forty,
+}
+
+impl Display for PlayerScore {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let score_text = match self {
+            Self::Love => "love",
+            Self::Fifteen => "15",
+            Self::Thirty => "30",
+            Self::Forty => "40",
+        };
+        write!(f, "{}", score_text)
+    }
+}
+
+impl PlayerScore {
+    fn next(self) -> Self {
+        match self {
+            Self::Love => Self::Fifteen,
+            Self::Fifteen => Self::Thirty,
+            Self::Thirty => Self::Forty,
+            Self::Forty => unreachable!("Cannot advance from Forty in regular scoring"),
+        }
+    }
+}
+
+#[derive(PartialEq, Copy, Clone)]
+pub enum Game {
+    Deuce,
+    Advantage(Player),
+    Win(Player),
+    Scores(PlayerScore, PlayerScore),
+}
+
+#[derive(PartialEq, Copy, Clone)]
+pub enum Player {
+    One,
+    Two,
+}
+
+impl Display for Player {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let player_text = match self {
+            Player::One => "Player 1",
+            Player::Two => "Player 2",
+        };
+        write!(f, "{}", player_text)
+    }
+}
+
+impl Default for Game {
+    fn default() -> Self {
+        Self::Scores(PlayerScore::Love, PlayerScore::Love)
+    }
+}
+
+impl Display for Game {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Deuce => f.write_str("Deuce"),
+            Self::Advantage(player) => write!(f, "Advantage {}", player),
+            Self::Win(player) => write!(f, "{} has won", player),
+            Self::Scores(player1_score, player2_score) if player1_score == player2_score => write!(f, "{}-all", player1_score),
+            Self::Scores(player1_score, player2_score) => write!(f, "{}-{}", player1_score, player2_score),
+        }
+    }
+}
+
+impl Game {
+    fn advance_score(self, player: Player) -> Self {
+        match (player, self) {
+            (x, Self::Advantage(y)) if x != y => Self::Deuce,
+            (Player::One, Self::Scores(PlayerScore::Thirty, PlayerScore::Forty)) => Self::Deuce,
+            (Player::Two, Self::Scores(PlayerScore::Forty, PlayerScore::Thirty)) => Self::Deuce,
+
+            (x, Self::Deuce) => Self::Advantage(x),
+
+            (x, Self::Advantage(y)) if x == y => Self::Win(x),
+            (Player::One, Self::Scores(PlayerScore::Forty, _)) => Self::Win(Player::One),
+            (Player::Two, Self::Scores(_, PlayerScore::Forty)) => Self::Win(Player::Two),
+
+            (Player::One, Self::Scores(player1_score, player2_score)) => {
+                Self::Scores(player1_score.next(), player2_score)
+            }
+            (Player::Two, Self::Scores(player1_score, player2_score)) => {
+                Self::Scores(player1_score, player2_score.next())
+            }
+            (_, x) => x,
+        }
+    }
+
+    pub fn score_point(&mut self, player: Player) {
+        *self = self.advance_score(player);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::*;
+
+    use rstest::rstest;
+
+    #[rstest]
+    #[case(vec!(0,0), "love-all")]
+    #[case(vec!(1,0), "15-love")]
+    #[case(vec!(2,0), "30-love")]
+    #[case(vec!(0,1), "love-15")]
+    #[case(vec!(3,0), "40-love")]
+    #[case(vec!(4,0), "Player 1 has won")]
+    #[case(vec!(3,3), "Deuce")]
+    #[case(vec!(3,3,1), "Advantage Player 1")]
+    #[case(vec!(3,3,2), "Player 1 has won")]
+    #[case(vec!(3,3,1,1), "Deuce")]
+    #[case(vec!(0,4), "Player 2 has won")]
+    #[case(vec!(1,1), "15-all")]
+    #[case(vec!(2,2), "30-all")]
+    #[case(vec!(1,2), "15-30")]
+    #[case(vec!(2,1), "30-15")]
+    #[case(vec!(3,3,0,1), "Advantage Player 2")]
+    #[case(vec!(3,3,0,2), "Player 2 has won")]
+    #[case(vec!(0,3,1), "15-40")]
+    #[case(vec!(3,3,1,1,0,1), "Advantage Player 2")]
+    #[case(vec!(3,3,1,1,1,1,0,2), "Player 2 has won")]
+    fn test_tennis_scoring(#[case] sequence: Vec<i32>, #[case] expected: &str) {
+        let mut game = Game::default();
+
+        let player_cycle = [Player::One, Player::Two].iter().cycle();
+        for (&n, player) in sequence.iter().zip(player_cycle) {
+            for _ in 0..n {
+                game.score_point(*player);
+            }
+        }
+
+        assert_eq!(game.to_string(), expected);
+    }
+}
diff --git a/glloyd_and_dbetteridge/src/main.rs b/glloyd_and_dbetteridge/src/main.rs
new file mode 100644
index 0000000..237dac4
--- /dev/null
+++ b/glloyd_and_dbetteridge/src/main.rs
@@ -0,0 +1,12 @@
+use tennis::{Game, Player};
+
+fn main() {
+    let mut game = Game::default();
+    println!("Starting game: {}", game);
+    
+    game.score_point(Player::One);
+    println!("After player 1 scores: {}", game);
+    
+    game.score_point(Player::Two);
+    println!("After player 2 scores: {}", game);
+}