diff --git a/src/fd.rs b/src/fd.rs
index 72e0bd6..2544537 100644
--- a/src/fd.rs
+++ b/src/fd.rs
@@ -6,7 +6,7 @@ use std::fs::File;
 use std::os::unix::fs::symlink;
 use bevy::tasks::ParallelSlice;
 use crate::system::spaces::square_grid::{Grid2D, Grid3D};
-use itertools::Itertools;
+use itertools::{Itertools, MinMaxResult};
 use clap::Parser;
 use crate::system::{GriddedPosition, Position};
 use crate::system::model::HistoryLine;
@@ -101,55 +101,19 @@ fn box_count_3d(data: &Vec<Grid3D>, size: u32) -> usize {
         .count();
 }
 
-fn box_count_nd<const N: usize, P: Position>(data: &Vec<P>, size: u32) -> usize {
-    let n = data.len();
-    let pp = data.iter().map(|op| op.to_cartesian()).collect::<Vec<P::Cartesian>>();
+fn box_count_nd<const N: usize>(data: &Vec<[f32; N]>, size: u32) -> usize {
+    let ranges = (0..N).map(|n|
+        match data.iter()
+            .minmax_by(|a, b| a[n].total_cmp(&b[n])) {
+            MinMaxResult::NoElements => panic!("No data"),
+            MinMaxResult::OneElement(_) => panic!("Needs more than one point to compute boxcount"),
+            MinMaxResult::MinMax(min, max) => [min[n], min[n]],
+        }).collect::<Vec<_>>();
 
-    let x_min = data
-        .iter()
-        .min_by(|Grid3D { x: x1, .. }, Grid3D { x: x2, .. }| x1.cmp(x2))
-        .unwrap().x;
+    let w: f32 = (ranges[0][1] - ranges[0][0]) / (size as f32);
 
-    let x_max = data
-        .iter()
-        .max_by(|Grid3D { x: x1, .. }, Grid3D { x: x2, .. }| x1.cmp(x2))
-        .unwrap().x;
-
-    let y_min = data
-        .iter()
-        .min_by(|Grid3D { y: v1, .. }, Grid3D { y: v2, .. }| v1.cmp(v2))
-        .unwrap().y;
-
-    let y_max = data
-        .iter()
-        .max_by(|Grid3D { y: v1, .. }, Grid3D { y: v2, .. }| v1.cmp(v2))
-        .unwrap().y;
-
-    let z_min = data
-        .iter()
-        .min_by(|Grid3D { z: v1, .. }, Grid3D { z: v2, .. }| v1.cmp(v2))
-        .unwrap().y;
-
-    let z_max = data
-        .iter()
-        .max_by(|Grid3D { z: v1, .. }, Grid3D { z: v2, .. }| v1.cmp(v2))
-        .unwrap().y;
-
-    let x_range = (x_max - x_min) as f64;
-    let y_range = (y_max - y_min) as f64;
-    let z_range = (z_max - z_min) as f64;
-
-    let w: f64 = x_range / (size as f64);
-
-    let grid_points = data.iter()
-        .map(|Grid3D { x, y, z }| [
-            ((x - x_min) as f64 / w) as u32,
-            ((y - y_min) as f64 / w) as u32,
-            ((z - z_min) as f64 / w) as u32,
-        ])
-        .collect::<Vec<_>>();
-
-    return grid_points.iter()
+    return data.iter()
+        .map(|point| -> [i32; N] { std::array::from_fn(|n| ((point[n] - ranges[n][0]) / w) as i32) })
         .unique()
         .count();
 }
@@ -165,10 +129,10 @@ fn main() {
         .expect("Failed to read json");
 
     let a = lines.iter()
-        .map(|l| l.position.clone())
+        .map(|l| l.position.to_cartesian())
         .collect::<Vec<_>>();
 
     for size in 1..250 {
-        println!("[{}, {:?}],", size, box_count_3d(&a, size));
+        println!("[{}, {:?}],", size, box_count_nd(&a, size));
     }
 }
diff --git a/src/system/spaces/square_grid.rs b/src/system/spaces/square_grid.rs
index bc2fa04..9598d5e 100644
--- a/src/system/spaces/square_grid.rs
+++ b/src/system/spaces/square_grid.rs
@@ -102,10 +102,26 @@ impl Add for Grid3D {
     type Output = Grid3D;
 
     fn add(self, rhs: Self) -> Self::Output {
-        Grid3D { x: self.x + rhs.x, y: self.y + rhs.y, z: self.z + rhs.z }
+        Grid3D {
+            x: self.x + rhs.x,
+            y: self.y + rhs.y,
+            z: self.z + rhs.z,
+        }
     }
 }
 
+#[test]
+fn grid3_add_test() {
+    assert_eq!(
+        Grid3D::from_cartesian([0f32, 0f32, 0f32]) + Grid3D::from_cartesian([0f32, 1f32, 0f32]),
+        Grid3D::from_cartesian([0f32, 1f32, 0f32])
+    );
+    assert_eq!(
+        Grid3D::from_cartesian([5.0, 3.0, 1.0]) + Grid3D::from_cartesian([-2.0, 5.0, 100.0]),
+        Grid3D::from_cartesian([3.0, 8.0, 101.0])
+    );
+}
+
 impl Position for Grid3D {
     type Cartesian = [f32; 3];
 
@@ -130,11 +146,25 @@ impl Position for Grid3D {
     }
 }
 
+#[test]
+fn grid3_neighbours_test() {
+    let neighbours = (0..Grid3D::NEIGHBOURS)
+        .map(|n| Grid3D::neighbour(&Grid3D::zero(), n))
+        .collect::<Vec<_>>();
+
+    assert!(neighbours.contains(&Grid3D { x: 1, y: 0, z: 0 }));
+    assert!(neighbours.contains(&Grid3D { x: -1, y: 0, z: 0 }));
+    assert!(neighbours.contains(&Grid3D { x: 0, y: 1, z: 0 }));
+    assert!(neighbours.contains(&Grid3D { x: 0, y: -1, z: 0 }));
+    assert!(neighbours.contains(&Grid3D { x: 0, y: 0, z: 1 }));
+    assert!(neighbours.contains(&Grid3D { x: 0, y: 0, z: -1 }));
+}
+
 impl GriddedPosition for Grid3D {
     const NEIGHBOURS: u32 = 6;
 
     fn neighbour(&self, neighbour_index: u32) -> Self {
-        let (dim, sign) = neighbour_index.div_rem(&3);
+        let (dim, sign) = neighbour_index.div_rem(&2);
         let sign = if sign == 0 { 1 } else { -1 };
         let offset = Self::in_direction(dim, sign);