message: increase stone size
diff: <visual name='visual'>
  <geometry>
  <box>
  - <size>0.02 0.032 0.064</size>
  + <size>0.025 0.032 0.064</size>
  </box>
  </geometry>
  <material>
  <pose>0 0 0 0 -0 0</pose>
  <geometry>
  <box>
  - <size>0.02 0.032 0.064</size>
  + <size>0.025 0.032 0.064</size>
  </box>
  </geometry>
  <surface>
  