About 100 BC the thousand flower process for making open beakers and shallow dishes was developed in Alexandria. A shaped core was made of mud, to which sections of colored glass canes were attached. The core and canes were placed into an outer mold to keep the shape while the glass fused in an oven. The glass surfaces were ground smooth after the core was removed and a striking mosaic effect was obtained through the cross sections of the colored rods.Phoenicians learned how to blow glass with a blowing iron near the beginning of the Christian era. An iron tube about 5 feet long, with a mouthpiece at one end and a knob for holding soft glass at the other end was used as the blowing iron. Molten glass was gathered on the knob end and rolled into a desirable shape on a flat surface of iron or stone called the marver. The shape was then blown inside a mold or freely in air with frequent reheating. The pontil - a solid iron rod was used to wrap, twirl, or pinch glass into desired designs. The handle, stem, or bottom could also be fused to the vessel when desired.Reference site:https://www.britannica.com/topic/glass-properties-composition-and-industrial-production-234890/History-of-glassmaking