diff --git a/src/display3d.rs b/src/display3d.rs
index e524538..e92dd98 100644
--- a/src/display3d.rs
+++ b/src/display3d.rs
@@ -47,22 +47,15 @@ impl Plugin for Display3dPlugin {
             .add_systems(
                 Update,
                 (
-                    move_camera
-                        .run_if(resource_exists::<debug::DebugEnabled>())
-                        .run_if(in_state(GameState::Play))
-                        .run_if(in_state(DisplayState::Display3d))
-                        .run_if(on_event::<MouseMotion>()),
-                    gizmo_system
-                        .run_if(resource_exists::<debug::DebugEnabled>())
-                        .run_if(in_state(GameState::Play))
-                        .run_if(in_state(DisplayState::Display3d)),
-                    mouse_zoom
-                        .run_if(resource_exists::<debug::DebugEnabled>())
-                        .run_if(in_state(GameState::Play))
-                        .run_if(in_state(DisplayState::Display3d))
-                        .run_if(on_event::<MouseWheel>()),
-                    selected_gizmo.run_if(resource_exists::<debug::DebugEnabled>()),
-                ),
+                    move_camera.run_if(on_event::<MouseMotion>()),
+                    mouse_zoom.run_if(on_event::<MouseWheel>()),
+                    gizmo_system,
+                    selected_gizmo,
+                    moves_gizmo,
+                )
+                    .run_if(resource_exists::<debug::DebugEnabled>())
+                    .run_if(in_state(GameState::Play))
+                    .run_if(in_state(DisplayState::Display3d)),
             )
             .add_systems(
                 OnEnter(DisplayState::Display3d),
@@ -516,14 +509,7 @@ fn select(
 }
 
 fn selected_gizmo(
-    selected: Query<
-        &Transform,
-        (
-            With<game::Selected>,
-            With<game::Selectable>,
-            With<Display3d>,
-        ),
-    >,
+    selected: Query<&Transform, (With<game::Selected>, With<Display3d>)>,
     mut gizmos: Gizmos,
 ) {
     selected.iter().for_each(|transform| {
@@ -531,6 +517,20 @@ fn selected_gizmo(
     })
 }
 
+fn moves_gizmo(
+    selected: Query<&BoardIndex, (With<game::Piece>, With<game::Selected>, With<Display3d>)>,
+    board: Res<Board>,
+    mut gizmos: Gizmos,
+) {
+    selected.iter().for_each(|idx| {
+        board
+            .possible_moves(*idx)
+            .iter()
+            .map(|i| Transform::from_translation(board_translation(i)))
+            .for_each(|t| gizmos.cuboid(t, Color::WHITE))
+    });
+}
+
 fn pick_up(
     mut events: Query<
         (Entity, &game::Piece),
diff --git a/src/game.rs b/src/game.rs
index f9d253a..733ed0f 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -1,3 +1,5 @@
+use bevy::utils::HashSet;
+
 use crate::prelude::*;
 
 pub(crate) struct GamePlugin;
@@ -20,6 +22,14 @@ impl Plugin for GamePlugin {
                     deselect_sync.run_if(any_component_removed::<Selected>()),
                     move_piece.run_if(any_component_added::<Selected>),
                     capture_piece.run_if(any_component_added::<Captured>),
+                    null_selections.run_if(any_component_added::<Selected>),
+                ),
+            )
+            .add_systems(
+                PostUpdate,
+                (
+                    asserts::<display2d::Display2d>,
+                    asserts::<display3d::Display3d>,
                 ),
             )
             .add_systems(
@@ -110,7 +120,7 @@ pub(crate) struct Move {
     pub to: Option<BoardIndex>,
 }
 
-#[derive(Debug, Component, PartialEq, Clone, Default, Copy)]
+#[derive(Debug, Component, PartialEq, Clone, Default, Copy, Eq, Hash)]
 pub(crate) struct BoardIndex {
     pub x: usize,
     pub y: usize,
@@ -196,24 +206,46 @@ impl Board {
     }
 
     /// Returns the possible moves the piece at this tile can make.
-    pub(crate) fn possible_moves(&self, BoardIndex { x, y }: BoardIndex) -> Vec<BoardIndex> {
+    pub(crate) fn possible_moves(&self, BoardIndex { x, y }: BoardIndex) -> HashSet<BoardIndex> {
         match self.at(BoardIndex { x, y }) {
             // One space in any diagonal
-            Some(Piece::Pawn) => {
-                self.at(BoardIndex { x: x + 1, y });
-                vec![]
-            }
+            Some(Piece::Pawn) => (-1..=1)
+                .flat_map(move |xi| {
+                    (-1..=1).map(move |yi| BoardIndex {
+                        x: x.checked_add_signed(xi).map_or(0, |val| val).clamp(0, 7),
+                        y: y.checked_add_signed(yi).map_or(0, |val| val).clamp(0, 3),
+                    })
+                })
+                .collect(),
             // One or two spaces in either horizontal
-            Some(Piece::Drone) => {
-                todo!("Where can a drone move?");
-                vec![]
-            }
+            Some(Piece::Drone) => std::iter::empty()
+                .chain((-2..=2).map(|i| BoardIndex {
+                    x: x.checked_add_signed(i).map_or(0, |val| val).clamp(0, 7),
+                    y,
+                }))
+                .chain((-2..=2).map(|i| BoardIndex {
+                    x,
+                    y: y.checked_add_signed(i).map_or(0, |val| val).clamp(0, 3),
+                }))
+                .collect(),
             // Any distance in any straight line
-            Some(Piece::Queen) => {
-                todo!("Where can a queen move?");
-                vec![]
-            }
-            None => Vec::new(),
+            Some(Piece::Queen) => std::iter::empty()
+                .chain((-7..=7).map(|i| BoardIndex {
+                    x: x.checked_add_signed(i).map_or(0, |val| val).clamp(0, 7),
+                    y,
+                }))
+                .chain((-3..=3).map(|i| BoardIndex {
+                    x,
+                    y: y.checked_add_signed(i).map_or(0, |val| val).clamp(0, 3),
+                }))
+                .chain((-3..=3).flat_map(move |xi| {
+                    (-3..=3).map(move |yi| BoardIndex {
+                        x: x.checked_add_signed(xi).map_or(0, |val| val).clamp(0, 7),
+                        y: y.checked_add_signed(yi).map_or(0, |val| val).clamp(0, 3),
+                    })
+                }))
+                .collect(),
+            None => std::iter::empty().collect(),
         }
     }
 }
@@ -301,15 +333,13 @@ fn debug_board(board: Res<Board>, mut debug_info: ResMut<debug::DebugInfo>) {
 /// Only update the tiles without a corresponding board piece
 pub(crate) fn update_board(
     mut events: EventReader<Move>,
-    mut pieces: Query<(Entity, &mut BoardIndex), (With<Piece>, Without<Tile>)>,
-    tiles: Query<(Entity, &BoardIndex), (With<Tile>, Without<Piece>)>,
+    mut pieces: Query<(Entity, &mut BoardIndex), With<Piece>>,
+    selected: Query<Entity, With<Selected>>,
     mut commands: Commands,
 ) {
     events.iter().for_each(|Move { from, to, .. }| {
-        pieces
-            .iter_mut()
-            .filter(|(_, index)| **index == *from)
-            .for_each(|(entity, mut index)| {
+        pieces.iter_mut().for_each(|(entity, mut index)| {
+            if *index == *from {
                 match to {
                     Some(to_idx) => {
                         *index = to_idx.clone();
@@ -321,14 +351,11 @@ pub(crate) fn update_board(
                             .insert(Captured);
                     }
                 }
-                commands.entity(entity).remove::<Selected>();
-            });
-        tiles
-            .iter()
-            .filter_map(|(entity, idx)| (Some(idx) == to.as_ref() || idx == from).then_some(entity))
-            .for_each(|entity| {
-                commands.entity(entity).remove::<Selected>();
-            });
+            }
+        });
+        selected.iter().for_each(|entity| {
+            commands.entity(entity).remove::<Selected>();
+        });
     })
 }
 
@@ -381,7 +408,7 @@ fn deselect_sync(
 }
 
 /// Triggered when right-mouse-button clicked
-fn cancel_place(current: Query<Entity, (With<Selected>, With<Piece>)>, mut commands: Commands) {
+fn cancel_place(current: Query<Entity, With<Selected>>, mut commands: Commands) {
     current.iter().for_each(|entity| {
         info!("De-selecting {:?}", entity);
         commands.entity(entity).remove::<Selected>();
@@ -390,13 +417,12 @@ fn cancel_place(current: Query<Entity, (With<Selected>, With<Piece>)>, mut comma
 
 /// When a tile is selected, move all selected pieces to that index
 fn move_piece(
-    events: Query<(Entity, &BoardIndex), (With<BoardIndex>, Added<Selected>)>,
+    events: Query<&BoardIndex, (With<BoardIndex>, Added<Selected>)>,
     selected_pieces: Query<&BoardIndex, (With<Selected>, With<Piece>)>,
     mut board: ResMut<Board>,
-    mut commands: Commands,
     mut move_events: EventWriter<Move>,
 ) {
-    events.iter().for_each(|(tile, to)| {
+    events.iter().for_each(|to| {
         selected_pieces.iter().for_each(|from| {
             // Move piece
             match board.move_piece(*from, *to) {
@@ -412,6 +438,20 @@ fn move_piece(
     });
 }
 
+/// De-select anything that shouldn't be selected
+/// Namely tiles when there are not selected pieces
+fn null_selections(
+    events: Query<Entity, Added<Selected>>,
+    selected_pieces: Query<Entity, (With<Selected>, With<Piece>)>,
+    mut commands: Commands,
+) {
+    events.iter().for_each(|entity| {
+        if selected_pieces.is_empty() {
+            commands.entity(entity).remove::<Selected>();
+        }
+    });
+}
+
 /// When a piece's _BoardIndex_ is removed, we hide that entity from the viewer
 fn capture_piece(mut events: Query<&mut Visibility, Added<Captured>>) {
     events.iter_mut().for_each(|mut vis| {
@@ -419,3 +459,19 @@ fn capture_piece(mut events: Query<&mut Visibility, Added<Captured>>) {
         *vis = Visibility::Hidden
     });
 }
+
+/// Panics if more than two pieces are selected at a time
+fn asserts<T: Component>(
+    selected_pieces: Query<Entity, (With<Piece>, With<T>, With<Selected>)>,
+    selected_tiles: Query<Entity, (With<Tile>, With<T>, With<Selected>)>,
+) {
+    if selected_pieces.iter().len() > 2 {
+        panic!("More than two piece is selected");
+    }
+    if selected_tiles.iter().len() > 1 {
+        panic!(
+            "More than one tile is selected {:?}",
+            selected_tiles.iter().len()
+        );
+    }
+}