--- a
+++ b/examples/under-construction/arm.py
@@ -0,0 +1,81 @@
+import os
+from osim.env import OsimEnv
+import pprint
+import numpy as np
+
+class Arm3dEnv(OsimEnv):
+    model_path = os.path.join(os.path.dirname(__file__), '../osim/models/MoBL_ARMS_J_Simple_032118.osim')
+    time_limit = 200
+    current_objective = np.array([0,0,0])
+    
+    def is_done(self):
+        # End the simulation if the pelvis is too low
+        state_desc = self.get_state_desc()
+        return False
+
+    def get_observation(self):
+        state_desc = self.get_state_desc()
+
+        # Augmented environment from the L2R challenge
+        res = []
+
+        # Map some of the state variables to the observation vector
+        for body_part in state_desc["body_pos_rot"].keys():
+            res = res + state_desc["body_pos_rot"][body_part][2:]
+            res = res + state_desc["body_pos"][body_part][0:2]
+            res = res + state_desc["body_vel_rot"][body_part][2:]
+            res = res + state_desc["body_vel"][body_part][0:2]
+            res = res + state_desc["body_acc_rot"][body_part][2:]
+            res = res + state_desc["body_acc"][body_part][0:2]
+
+        for joint in state_desc["joint_pos"].keys():
+            res = res + state_desc["joint_pos"][joint]
+            res = res + state_desc["joint_vel"][joint]
+            res = res + state_desc["joint_acc"][joint]
+
+        res = res + state_desc["misc"]["mass_center_pos"] + state_desc["misc"]["mass_center_vel"] + state_desc["misc"]["mass_center_acc"]
+        res += self.current_objective.tolist()
+
+        res = np.array(res)
+        res[np.isnan(res)] = 0
+
+        return res
+
+    def get_observation_space_size(self):
+        return 168
+
+    def reset_objective(self):
+        self.current_objective = np.random.uniform(-0.5,0.5,3)
+
+    def reset(self):
+        print(self.reward())
+        self.reset_objective()
+        return super(Arm3dEnv, self).reset()
+
+    def reward(self):
+        # Get the current state and the last state
+        prev_state_desc = self.get_prev_state_desc()
+        if not prev_state_desc:
+            return 0
+        state_desc = self.get_state_desc()
+
+        res = 0
+
+        # # Penalize movement of the pelvis
+        # res = -(prev_state_desc["misc"]["mass_center_pos"][0] - state_desc["misc"]["mass_center_pos"][0])**2\
+        #       -(prev_state_desc["misc"]["mass_center_pos"][1] - state_desc["misc"]["mass_center_pos"][1])**2
+
+        # # Penalize very low position of the pelvis
+        # res += -(state_desc["joint_pos"]["ground_pelvis"][2] < 0.8)
+        
+        return -np.linalg.norm(np.array(state_desc["markers"]["Handle"]["pos"]) - self.current_objective)
+
+env = Arm3dEnv(visualize=True)
+
+if __name__ == '__main__':
+    observation = env.reset()
+    for i in range(200):
+        action = env.action_space.sample()
+        observation, reward, done, info = env.step(action)
+        if done:
+            env.reset()