diff --git a/src/lib/ai.rs b/src/lib/ai.rs
index 0aebb09..5347289 100644
--- a/src/lib/ai.rs
+++ b/src/lib/ai.rs
@@ -56,12 +56,8 @@ impl AI for Ant {
         if !choice.is_none() {
             let pos = choice.unwrap();
             if w.cleared.contains(&pos) {
-                let old_pos = self.pos;
                 self.pos = pos;
-                w.update_occupied(&old_pos, &pos);
-            } else {
-                w.clear(pos);
-            }
+            }         
         }
 
         BoardCommand::Noop
@@ -94,9 +90,7 @@ impl AI for Queen {
                     self.egg_count += 1;
                     return BoardCommand::LayEgg(pos, self.id);
                 } else {
-                    let old_pos = self.pos;
                     self.pos = pos;
-                    w.update_occupied(&old_pos, &pos);
                 }
             }
         }
diff --git a/src/lib/point.rs b/src/lib/point.rs
index 084e3c7..3727ba4 100644
--- a/src/lib/point.rs
+++ b/src/lib/point.rs
@@ -6,12 +6,49 @@ pub struct Point(pub i32, pub i32);
 impl Point {
     pub fn get_neighbors(&self) -> Vec<Point> {
         vec![
-            Point(self.0, self.1 + 1),
-            Point(self.0, self.1 - 1),
-            Point(self.0 - 1, self.1),
-            Point(self.0 + 1, self.1),
+            self.left(),
+            self.right(),
+            self.up(),
+            self.down()
         ]
     }
+
+    pub fn is_above(&self, other: &Point) -> bool {
+        other.up() == *self
+    }
+
+    pub fn is_below(&self, other: &Point) -> bool {
+        other.down() == *self
+    }
+
+    pub fn is_left(&self, other: &Point) -> bool {
+        other.left() == *self
+    }
+
+    pub fn is_right(&self, other:&Point) -> bool {
+        other.right() == *self
+    }
+
+    pub fn is_adjacent(&self, other: &Point) -> bool {
+        other.is_left(self) || other.is_right(self)
+    }
+
+    pub fn left(&self) -> Point {
+        Point(self.0 - 1, self.1)
+    }
+
+    pub fn right(&self) -> Point {
+        Point(self.0 + 1, self.1)
+    }
+
+    // y values are reversed in ncurses
+    pub fn down(&self) -> Point {
+        Point(self.0, self.1 + 1)
+    }
+
+    pub fn up(&self) -> Point {
+        Point(self.0, self.1 - 1)
+    }
 }
 
 fn manhattan(c1: &Point, c2: &Point) -> i32 {
diff --git a/src/lib/screen.rs b/src/lib/screen.rs
index 8b07159..0a2d911 100644
--- a/src/lib/screen.rs
+++ b/src/lib/screen.rs
@@ -32,7 +32,7 @@ impl Screen {
     }
 
     pub fn is_in_bounds(&self, pos: &Point) -> bool {
-        (pos.0 > -self.max_x && pos.0 < self.max_x) && (pos.1 > -self.max_y && pos.1 < self.max_y)
+        (pos.0 >= 0 && pos.0 < self.max_x) && (pos.1 >= 0 && pos.1 < self.max_y)
     }
 
     pub fn get_valid_movements(&self, pos: &Point) -> Vec<Point> {
@@ -45,7 +45,7 @@ impl Screen {
     }
 
     pub fn render(&self, p: &Point, char: &str) {
-        mvprintw(p.1 + self.center.1, p.0 + self.center.0, char);
+        mvprintw(p.1, p.0, char);
     }
 
     pub fn get_dimensions(&self) -> (Point, Point) {
diff --git a/src/lib/world.rs b/src/lib/world.rs
index b851498..9c009b5 100644
--- a/src/lib/world.rs
+++ b/src/lib/world.rs
@@ -1,21 +1,19 @@
-use crate::lib::screen::{Screen, BoardCommand};
+use crate::lib::entity::{Ant, Egg, Entities, Food, Queen};
 use crate::lib::point::Point;
-use crate::lib::entity::{Entities, Queen, Egg, Ant, Food};
+use crate::lib::screen::{BoardCommand, Screen};
 use std::collections::HashSet;
 
 #[derive(Clone)]
 pub struct World {
     pub cleared: HashSet<Point>,
-    pub occupied: HashSet<Point>,
-    pub food: HashSet<u32>
+    pub food: HashSet<u32>,
 }
 
 impl World {
     pub fn new() -> World {
         World {
             cleared: HashSet::new(),
-            occupied: HashSet::new(),
-            food: HashSet::new()
+            food: HashSet::new(),
         }
     }
 
@@ -23,23 +21,34 @@ impl World {
         self.cleared.insert(pos);
     }
 
-    pub fn is_valid_movement(&self, pos: &Point, b: &Screen) -> bool {
-        b.is_in_bounds(pos) && !self.occupied.contains(pos)
+    pub fn is_valid_movement(&self, current_pos: &Point, target: &Point, b: &Screen) -> bool {
+        let mut safe = true;
+
+        if target.is_above(current_pos) {
+            safe =
+                !self.cleared.contains(&target.left()) || !self.cleared.contains(&target.right());
+        }
+
+        if target.is_adjacent(current_pos) {
+            let target_down = target.down();
+            if self.cleared.contains(&target_down) {
+                safe = !self.cleared.contains(&target_down.left())
+                    || !self.cleared.contains(&target_down.right());
+            } else {
+                safe = !self.cleared.contains(&target.down());
+            }
+        }
+        b.is_in_bounds(target) && safe
     }
 
     pub fn get_valid_movements(&self, pos: &Point, b: &Screen) -> Vec<Point> {
         let moves = b.get_valid_movements(pos);
         moves
             .iter()
-            .filter(|p| !self.occupied.contains(p))
+            .filter(|p| self.is_valid_movement(pos, p, b))
             .map(|p| p.clone())
             .collect()
     }
-
-    pub fn update_occupied(&mut self, old: &Point, new: &Point) {
-        self.occupied.remove(old);
-        self.occupied.insert(*new);
-    }
 }
 
 pub fn render(e: &Entities, w: &World, b: &Screen) {
@@ -56,9 +65,9 @@ pub fn simulate(e: &mut Entities, w: &mut World, b: &mut Screen) {
     let cmds: Vec<BoardCommand> = e
         .data
         .values_mut()
-        .map(|a| { 
+        .map(|a| {
             a.plan(w);
-            a.step(b, w) 
+            a.step(b, w)
         })
         .collect();
 
@@ -83,7 +92,7 @@ pub fn simulate(e: &mut Entities, w: &mut World, b: &mut Screen) {
             }
             BoardCommand::SpawnFood(pos) => {
                 let food = Food::new(pos.0, pos.1);
-                e.add_entity(&food); 
+                e.add_entity(&food);
             }
             BoardCommand::Noop => {}
         }
diff --git a/src/main.rs b/src/main.rs
index 2bfef4a..9d66608 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,12 +24,17 @@ fn main() {
     let mut world = World::new();
 
     let mut entities = Entities::new();
-    let q = Queen::new(0,0);
+    let q = Queen::new(3,0);
     entities.add_entity(&q);
 
-    for i in -3..3 {
-        for j in -3..3 {
-            world.clear(Point(i, j));
+    for i in 0..6 {
+        for j in 0..6 {
+            if j != 1 {
+                world.clear(Point(i, j));
+            } else {
+                world.clear(Point(0, j));
+                world.clear(Point(5, j));
+            }
         }
     }
 
@@ -37,7 +42,7 @@ fn main() {
         // TODO: add way to break out of the loop by hitting a random key
         simulate(&mut entities, &mut world, &mut board);
         render(&entities, &world, &board);
-        sleep(time::Duration::from_millis(100));
+        sleep(time::Duration::from_millis(1000));
         refresh();
     }
     endwin();