I saw some neat clock designs from a clock company in Latvia. Some of these had a rounded or curved top, in one piece of glass. My stained glass instructor says it takes a special mold and furnace to make these curved tops.
But I then ran across a clock design which made the curved top with segmented pieces of glass, instead of just one piece. I found it searching Facebook for "stained glass clocks".
Using the segmented method would allow me to make clocks like the Latvia company's clocks.....without the need for a special 1-piece curved top.
I may make a stained glass clock with a curved clock someday.