diff --git a/src/grid.rs b/src/grid.rs
index 144ef46..cc49c3d 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -88,6 +88,8 @@ pub struct Grid {
     // Scratch space for the blur operation.
     buf: Vec<f32>,
     blur: Blur,
+
+    pub i: Vec<usize>,
 }
 
 impl Clone for Grid {
@@ -99,13 +101,14 @@ impl Clone for Grid {
             data: self.data.clone(),
             buf: self.buf.clone(),
             blur: self.blur.clone(),
+            i: self.i.clone(),
         }
     }
 }
 
 impl Grid {
     // Create a new grid filled with random floats in the [0.0..1.0) range.
-    pub fn new<R: Rng + ?Sized>(width: usize, height: usize, rng: &mut R) -> Self {
+    pub fn new<R: Rng + ?Sized>(width: usize, height: usize, rng: &mut R, i: Vec<usize>) -> Self {
         if !width.is_power_of_two() || !height.is_power_of_two() {
             panic!("Grid dimensions must be a power of two.");
         }
@@ -119,6 +122,7 @@ impl Grid {
             config: PopulationConfig::new(rng),
             buf: vec![0.0; width * height],
             blur: Blur::new(width),
+            i,
         }
     }
 
diff --git a/src/main.rs b/src/main.rs
index dd3cff5..8016e31 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,20 +2,22 @@ use physarum::model;
 
 fn main() {
     // # of iterations to go through
-    let n_iterations = 2048;
+    let n_iterations = 256;
 
     // Size of grid and pictures
     let (width, height) = (256, 256);
     // let (width, height) = (1024, 1024);
 
     // # of agents
-    let n_particles = 1 << 20;
+    // let n_particles = 1 << 20;
+    let n_particles = 1 << 16;
     println!("n_particles: {}", n_particles);
 
     let diffusivity = 1;
 
     // `n_populations` is the # of types of agents
-    let n_populations = 1;
+    // let n_populations = 1;
+    let n_populations = 3;
     // let n_populations = 1 + rng.gen_range(1..4); // make # of populations between 2 and 5
 
     let mut model = model::Model::new(width, height, n_particles, n_populations, diffusivity); // Create the model
diff --git a/src/model.rs b/src/model.rs
index fba6ca2..6dd65cc 100644
--- a/src/model.rs
+++ b/src/model.rs
@@ -126,11 +126,11 @@ impl Model {
         }
 
         Model {
-            agents: (0..n_particles)
+            agents: (0..(n_particles-1))
                 .map(|i| Agent::new(width, height, i / particles_per_grid, &mut rng, i))
                 .collect(),
             grids: (0..n_populations)
-                .map(|_| Grid::new(width, height, &mut rng))
+                .map(|_| Grid::new(width, height, &mut rng, vec![]))
                 .collect(),
             attraction_table,
             diffusivity,
@@ -156,6 +156,24 @@ impl Model {
 
         let mut time_per_agent_list: Vec<f64> = Vec::new();
         let mut time_per_step_list: Vec<f64> = Vec::new();
+
+
+        println!("Doing some population stuff...");
+        let time_1 = Instant::now();
+        let mut i_pop: Vec<Vec<usize>> = Vec::new();
+        for i in (0..(self.grids.len())) {
+            i_pop.push(vec![]);
+        }
+        for agent in self.agents.iter() {
+            i_pop[agent.population_id].push(agent.i);
+        }
+        
+        for i in (0..(self.grids.len())) {
+            self.grids[i].i = i_pop[i].clone();
+        }        
+        println!("Took {}ms", time_1.elapsed().as_millis());
+
+        let use_exp_deposit: bool = true;
         for i in 0..steps {
             if debug {
                 println!("Starting tick for all agents...")
@@ -222,9 +240,19 @@ impl Model {
                 );
             });
 
-            // Deposit // TODO - Make this parallel
-            for agent in self.agents.iter() {
-                self.grids[agent.population_id].deposit(agent.x, agent.y);
+            // Deposit
+            if use_exp_deposit {
+                let agent_list = self.agents.clone();
+                self.grids.par_iter_mut().for_each(|grid|{
+                    for i in (0..grid.i.len()) {
+                        let agent = &agent_list[i];
+                        grid.deposit(agent.x, agent.y);
+                    }
+                });
+            } else {
+                for agent in self.agents.iter() {
+                    self.grids[agent.population_id].deposit(agent.x, agent.y);
+                }
             }
 
             // Diffuse + Decay