diff --git a/src/main.rs b/src/main.rs
index c9089fd..b8705c7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,7 @@
 use rand::Rng;
-use std::fmt;
+use std::collections::HashSet;
+use std::io::Write;
+use std::{fmt, io, process};
 
 #[derive(Clone, Copy)]
 struct Cell {
@@ -40,65 +42,205 @@ struct Grid(Vec<Vec<Cell>>);
 
 impl fmt::Display for Grid {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut y = 'a' as u8;
         for row in self.0.iter() {
+            write!(f, "{:2} ", y as char)?;
+            y += 1;
+
             for cell in row.iter() {
                 write!(f, " {} ", cell)?;
             }
             write!(f, "\n")?;
         }
+
+        write!(f, "{:2} ", "")?;
+        let mut col = 0;
+        for _ in self.0[0].iter() {
+            write!(f, "{:2} ", col)?;
+            col += 1;
+        }
         Ok(())
     }
 }
 
-fn mark_neighbors(grid: &mut Grid, x: usize, y: usize) {
-    for row in y.saturating_sub(1)..=y.saturating_add(1) {
-        for col in x.saturating_sub(1)..=x.saturating_add(1) {
-            if x == col && y == row {
+impl Grid {
+    fn plant_mines_and_set_neighbors(&mut self, mines: u8) {
+        let mut rng = rand::thread_rng();
+
+        let mut mines_left = mines;
+        while mines_left > 0 {
+            let row = rng.gen_range(0..self.0.len());
+            let col = rng.gen_range(0..self.0[0].len());
+            let cell: &mut Cell = &mut self.0[row][col];
+            if cell.mine {
                 continue;
             }
 
-            let Some(cell) = grid.0.get_mut(row).and_then(|row| row.get_mut(col)) else {
-                continue;
-            };
+            mines_left -= 1;
+            cell.mine = true;
+            self.on_neighbors(col, row, |cell, _| cell.neighbors += 1);
+        }
+    }
 
-            cell.neighbors += 1;
+    pub fn new(rows: usize, cols: usize, mines: u8) -> Option<Self> {
+        if rows < 1 || cols < 1 {
+            return None;
+        }
+
+        let mut grid: Grid = Grid(vec![
+            vec![
+                Cell {
+                    neighbors: 0,
+                    flagged: false,
+                    mine: false,
+                    revealed: false,
+                };
+                rows
+            ];
+            cols
+        ]);
+        grid.plant_mines_and_set_neighbors(mines);
+
+        return Some(grid);
+    }
+}
+
+enum GridCommand {
+    REVEAL((usize, usize)),
+    FLAG((usize, usize)),
+}
+
+struct GameState {
+    grid: Grid,
+    win: bool,
+    turn: u32,
+}
+
+impl fmt::Display for GameState {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "turn({})\n", self.turn)?;
+        write!(f, "{}", self.grid)?;
+
+        Ok(())
+    }
+}
+
+fn parse_coord(coord: &str) -> Result<(usize, usize), &'static str> {
+    let mut parts = coord.chars();
+    if coord.len() < 2 {
+        return Err("expected at least two characters when parsing coordinate");
+    }
+
+    let mut y: usize = 0;
+    let mut x: usize = 0;
+    loop {
+        let Some(next) = parts.next() else {
+            break;
+        };
+        if next >= 'a' && next <= 'z' {
+            y = ((next as u8) - 'a' as u8) as usize;
+        }
+        if next >= '0' && next <= '9' {
+            x = ((next as u8) - '0' as u8) as usize;
+        }
+    }
+
+    return Ok((y, x));
+}
+
+fn parse_command(cmd: &str) -> Result<GridCommand, &'static str> {
+    let mut parts = cmd.split_whitespace();
+
+    if parts.clone().count() == 1 {
+        if let Some(coord_str) = parts.next() {
+            match parse_coord(coord_str) {
+                Ok(coord) => return Ok(GridCommand::REVEAL(coord)),
+                Err(e) => return Err(e),
+            }
+        } else {
+            return Err("Can't get coordinate part of command");
+        }
+    }
+
+    let command_part = parts.next().ok_or("Can't get command part of input")?;
+    let coord_str = parts.next().ok_or("Can't get coordinate part of command")?;
+
+    let coord = parse_coord(coord_str).or(Err("Invalid coordinates"))?;
+
+    match command_part.to_lowercase().as_str() {
+        "flag" => Ok(GridCommand::FLAG(coord)),
+        "reveal" => Ok(GridCommand::REVEAL(coord)),
+        _ => Err("Unknown command"),
+    }
+}
+
+fn reveal_at(game_state: &mut GameState, coord: (usize, usize)) {
+    let mut seen = HashSet::new();
+    let mut stack = Vec::<(usize, usize)>::new();
+    stack.push(coord);
+
+    while let Some((y, x)) = stack.pop() {
+        if seen.contains(&coord) {
+            continue;
+        }
+        seen.insert(coord);
+
+        let Some(cell) = game_state.grid.0.get_mut(y).and_then(|row| row.get_mut(x)) else {
+            continue;
+        };
+        if cell.neighbors > 0 || cell.mine {
+            continue;
+        }
+
+        cell.revealed = true;
+
+        for row in y.saturating_sub(1)..=y.saturating_add(1) {
+            for col in x.saturating_sub(1)..=x.saturating_add(1) {
+                if x == col && y == row {
+                    continue;
+                }
+
+                stack.push((row, col));
+            }
         }
     }
 }
 
-fn plant_mines(grid: &mut Grid, mines: u8) {
-    let mut rng = rand::thread_rng();
-
-    let mut mines_left = mines;
-    while mines_left > 0 {
-        let row = rng.gen_range(0..grid.0.len());
-        let col = rng.gen_range(0..grid.0[0].len());
-        let cell: &mut Cell = &mut grid.0[row][col];
-
-        if !cell.mine {
-            mines_left -= 1;
-            cell.mine = true;
-
-            mark_neighbors(grid, col, row);
-        }
+fn play_game(game_state: &mut GameState) {
+    if game_state.win {
+        return;
     }
+
+    println!("{}\n", game_state);
+    print!("> ");
+    let _ = io::stdout().flush();
+
+    let mut buffer = String::new();
+    let stdin = io::stdin();
+    stdin.read_line(&mut buffer);
+
+    let cmd = match parse_command(buffer.as_str()) {
+        Ok(command) => command,
+        Err(e) => {
+            println!("error: {}", e);
+            return play_game(game_state);
+        }
+    };
+
+    game_state.turn += 1;
+    play_game(game_state);
 }
 
 fn main() {
-    let mut grid = Grid(vec![
-        vec![
-            Cell {
-                neighbors: 0,
-                flagged: false,
-                mine: false,
-                revealed: false,
-            };
-            9
-        ];
-        9
-    ]);
+    let Some(grid) = Grid::new(9, 9, 10) else {
+        eprintln!("failed to initialize grid");
+        process::exit(1);
+    };
 
-    plant_mines(&mut grid, 10);
-
-    println!("{}", grid);
+    let mut game_state = GameState {
+        grid,
+        win: false,
+        turn: 1,
+    };
+    play_game(&mut game_state);
 }