When we were on the Oregon coast, Susan and I stopped at this art glass studio. The glass was all blown and they had some pendant light Susan liked. But he didn't have the exact color she wanted. So he custom made her one and we got to watch him do it. It was pretty cool. He started by take a blob of white hot glass out of the furnace.
Then he repeatedly rolled it in colored chips. Blues and greens. Then he put it in what he called the glory hole. There was lots of shaping and pulling.
Then he blew his breath in it. The moisture in his breath expanded with the heat. Lots more shaping.
Finally, it had to cool slowly over night so that it wouldn't break. Ta da, here is the finished product. Isn't it beautiful.