How are the Pipes made Hollow?

These are frequently the opinion of someone being bare to 'hand blown' glass pipes for the first time. For starters, the raw glass is obtainable in both rods and tubes of unreliable sizes. Pieces of this tubing are rotated in the flame of a burn down, and animated until the glass is flexible (think of a sugar-daddy on a hot day, or honey at about room temp). Once the glass is in this semi-liquid state, it can be manipulated with a variety of tools, gravity, and by blowing into the hot tube. Patterns are added by applying tinted rod, and/or encasing fumed on metals (mostly gold and silver) with layers of clear glass. I realize this account raises many more questions than it answers, but the procedure is actually too concerned for me to go into more detail here.