A method of manufacturing a gas turbine engine fan blade comprises forming three metal workpieces. The drive circuit is particularly suitable for use with piezoelectric crystals. Wherein, the light-valving structure and the color-adjusting structure at least partially overlap on the traveling path of light, forming at least one overlapping structure. The rear entry divides at a junction into a first fiber groove and a second, diverging fiber groove. The content can be modified andor rendered to appear to be associated with the user in the rendered view. The duct includes a delivery pipe interposed between at least two tanks of the transfer liquid, and the turbine; respective pistons are configured to slide hermetically, alternately, and cyclically inside the two tanks for their alternating emptying and consequent sending of the liquid to the turbine through the delivery pipe.