MuJoCo viewer files - smith300 parametric arm.  Requires (once): pip install mujoco
Connectors are ROUNDED by default now.

Run from THIS folder:
  python -m mujoco.viewer --mjcf=two_servo.xml           # arm (rounded connectors, as-placed)
  python -m mujoco.viewer --mjcf=two_servo_aligned.xml   # arm with small placement shifts SNAPPED out (orthogonal connectors)
  python -m mujoco.viewer --mjcf=two_servo_fidex.xml     # arm + ArUco fiducial board on the base plate
  python -m mujoco.viewer --mjcf=arm_vs_yam.xml          # side-by-side with the YAM arm

Open the CONTROL panel (left) for a slider per joint (drive_output_0..5, yam_*).
Self-contained (all meshes + aruco png live here).