A yellow robotic arm is displayed. It has a base with one arm on a fixed joint. That arm connects to the second arm with a ball joint. The second arm has a post that inserts into the elbow ball joint. End of the second arm is connected to the hand with another fixed joint. The hand points down. The second arm is horizontal, and the first arm connects the second arm to the base at a slight angle to the right.
To illustrate Pitch, the hand rotates to horizontal and back to vertical on its fixed joint to illustrate Pitch. The second arm rotates straight up on its ball joint, back to horizontal, and then straight down, and then back to horizontal.
To illustrate Roll, the second arm twists on its post so the hand is pointing away from the viewer, back to center, and then twists on its post so the hand is pointing toward the viewer, and finally back to center.
To illustrate Yaw, the second arm rotates entirely away from the viewer on its ball joint, back to center, and then toward the viewer on its ball joint, and finally back to center.