Shaper is really a bit of a relic in the industry but the way it operates is that your workpiece is retained statically (via clamps or in a Vise typically) and you have a fixed blade cutter that has a contoured shape that moves in a straight toolpath To and Fro across the workpiece removing material each time the cutting edge makes contact. They can be set to travel a preset distance advancing in either Depth, Width, Length or all the above.