The top picture is of Larry working an aluminum piece on the power hammer for the Sikorsky Museum, the bottom picture is the original next to the formed piece. The black gridlines are a series of evenly spaced parallel marker lines which help reveal the form of the area being worked in relation to the whole piece as it is being reshaped. For this particular piece, we first created a moderately flexible pattern of the original part. This pattern was then used during the metal forming process as a height gauge for the surface - by laying it over the metal, we were able to depress an area and see how much the metal still had to be raised.