diff --git a/data.py b/data.py
index 40b7b8e..d9a2417 100644
--- a/data.py
+++ b/data.py
@@ -11,11 +11,11 @@ def parse_csv(filename: str):
         lines = file.read().strip().splitlines()
     pos = np.zeros((len(lines), 2))
     vel = np.zeros((len(lines), 2))
-    rad = np.zeros((len(lines),))
+    rad = np.zeros((len(lines), 1))
     for i, [x, y, vx, vy, r] in enumerate(map(lambda l: map(float, l.split(',')), lines)):
         pos[i] = [x, y]
         vel[i] = [vx, vy]
-        rad[i] = r
+        rad[i] = [r]
     return pos, vel, rad
 
 
diff --git a/physics.py b/physics.py
index 43060be..0d73b9e 100644
--- a/physics.py
+++ b/physics.py
@@ -8,10 +8,12 @@ def rotations(a: np.ndarray):
     a2 = np.concatenate((a, a))
     for i in range(1, len(a)):
         yield np.split(a2, [i, i + len(a)])[1]
+        # TODO: Compare performance
+        # yield np.roll(a, i)
 
 
 def n_body(pos: np.ndarray, vel: np.ndarray, mass: np.ndarray):
-    for (o_pos, o_mass) in zip(rotations(pos), rotations(mass[:, np.newaxis])):
+    for (o_pos, o_mass) in zip(rotations(pos), rotations(mass)):
         dist = o_pos - pos
         vel += G * (dist / np.linalg.norm(dist, axis=1)[:, np.newaxis]) * o_mass / np.sum(dist ** 2, axis=1)[:, np.newaxis]
     pos += vel