 Robots come in all different shapes and sizes, but are frequently classed by their degrees of freedom. Each direction of movement on the robot is considered an axis of movement. This robot rotates at the waist, bends forward and back at the shoulder, and moves vertically at the elbow. Each single movement axis is equal to one degree of freedom. This particular robot is equal to six degrees of freedom. It moves along one axis for each of the waist, shoulder and elbow joints and along three axes at the wrist using pitch, roll and yaw. These particular motions help to locate the tool in the work area and are called position axes. Most robots have at least three position axes to help position the tool in the work area. If the robot were to slide along a track, it would have a fourth position axis of linear movement and another degree of freedom. While the position axes locate the tool in the work area, the orientation axes help orient the tool in relation to the work piece. The types of movement along orientation axes are defined as pitch, roll and yaw. These movements all occur from the same joint, the wrist, but along three distinct axes. This type of movement is most easily illustrated as it relates to aircraft movement. The robot's tool moves in the same way. Pitch moves the tool vertically, roll rotates the tool about its center axis, yaw turns the tool left and right. The position axes movement at the waist, shoulder and elbow along with the orientation axes movement of pitch, roll and yaw allow the robot to accomplish its tasks within the work envelope.