A decorative process in which grooves are cut into the steel and filled with gold or silver wire. The steel is first warmed, then the design is engraved into it, leaving rough edges the better to give purchase to the inlaid material. The wire is pressed into the groove and either flattened by hammering or left in relief. It might then be reheated to restore the colour, or burnished. In spatial inlaying, the background of the design is chiselled away and filled with gold foil, leaving the design itself black against the gold ground.