Oldies but Goodies - Geometric shapes

Wow, time is racing and another week has gone by already without me being creative, well, except for a custom pair of spike bauble earrings.
I'm just glad we have the Jewelry Artisans Community Oldies but Goodies Challenge to remind me not only of my own creativity, but more so of that of others.
Our theme was geometric shapes and we really got to see some amazing beauties!

How many basic geometric shapes are there? Obviously people don't necessarily agree on the number, some say there are four - circle, triangle, square, and rectangle - others say six and add rhombus and trapezoid. As the math genius that I am not, I'll stay out of that.

I do remember, though, that we once had to make a piece of jewelry in school. The plan had been for us to learn how to use a simple tin-lead based solder. I made a pendant consisting of a triangle, circle, and a square if I remember right. It came out pretty lousy, but had a definite mod vibe which worked well as we were still barely in the 70s.
Anyhow, I guess geometric shapes in jewelry had already fascinated me then.

These following examples are so much better than my pendant was. Enjoy!

1 Cat's Wire
2 Jewelry Art by Dawn
3 My Bijou Life
4 RioRita Jewelry