A technique dating back to the sixteenth century used to manufacture glass objects composed of clear glass rods with a core of lattimo or colored glass filament. The rods are laid side by side, placed in the kiln, and fused together. They are then gathered at the end of the blow pipe on a cylinder of cristallo glass, which is then blown and shaped. This technique utilizes three different patterns: a mezza-filigrana, a reticello and a retortoli. In the a mezza-filigrana and a reticello patterns, rods with a single filament are used. A retortoli or zanfirico pattern is composed of at least two filaments woven into a spiral. A reticello is a pattern of diamond-shaped filaments obtained by merging, while twisting in the opposite directions, two half spheres of mezza filigrana. A more ancient variation of filigrana is the a retortoli, also known as zanfirico. This variation is named after the Venetian antiquarian Antonio Sanquirico who, during the first half of the nineteenth century, commissioned a large quantity of glass made using this particular technique. During the ’50s and ’60s maestro Archimede Seguso further developed the filigrana technique by inventing new interpretations called merletti using segments of specially prepared a retortoli rods.