diff --git a/src/model.rs b/src/model.rs
index 6e47c0e..7f42ee3 100644
--- a/src/model.rs
+++ b/src/model.rs
@@ -76,12 +76,14 @@ impl Model {
         }
 
         let mut grids: Vec<Grid> = Vec::new();
-        for _ in 0..n_populations {
+        for pop in 0..n_populations {
             let agents = (0..particles_per_grid)
-            .map(|i| Agent::new(width, height, i / particles_per_grid, &mut rng, i)).collect();
+                .map(|i| {
+                    Agent::new(width, height, pop, &mut rng, i)
+                }).collect();
             grids.push(Grid::new(width, height, &mut rng, agents));
-
         }
+
         Model {
             grids,
             attraction_table,