Shape of a Zulu Shield?

March 29, 2005 8:26 AM

Unsettled bar question: what is the shape of a Zulu Shield called?

Assume perfect symmetry. I thought it might be a Prolate spheroid, but that's 3D and looks as if it doesn't have the pointed ends needed to qualify.

posted by hellbient to science & nature (16 comments total)

Damn good question. The FOTW pages for Kenya and Swaziland don't give a formal name for the shape, unfortunately.
posted by Vidiot at 8:42 AM on March 29, 2005

I would call it "almond-shaped." Dunno if there's a more formal term for it.
posted by nebulawindphone at 8:54 AM on March 29, 2005

Symbols.com has some background on that shape and what it means symbol-wise. It may not have a geometric name.

The sign appears in the Egyptian hieroglyphic system. Drawn vertically, it much later became a symbol for Christ, vesica piscis, literally the air bladder of a fish. This sign is a symbol of virginity or purity. It often appears in a mandorla, i.e. surrounded by a radiating aurelia, or gloria, as in . The Cabbalistic mystics used to signify innocence.

posted by jessamyn at 8:58 AM on March 29, 2005

To me, the shield looks more football-shaped (American football-shaped, that is). Looking for football shapes, I found two definitions on this page. One agrees with your initial assumption, a prolate spheroid, and the other goes with a more generic ellipsoid. I think the 3D part doesn't matter quite so much, as I believe the middle section curves outward, right?
posted by Moondoggie at 9:02 AM on March 29, 2005

If you met me on the street and showed me that picture, my snap response would be "leaf-shaped", but that's only because I think I've heard zulu shields described as leaf-shaped. If it was just a picture of a generic shape with those qualities, I would say "almond-shaped". For whatever that is worth to you.
posted by Hildago at 9:05 AM on March 29, 2005

The shape can be seen in one of the iterations of the Ellipse Negative Pedal Curve. I thought Lozenge best described it, but apparently that's technically not rounded, but more like a rhombus.
posted by odinsdream at 9:05 AM on March 29, 2005

Ooh, even better.. Talbot's Curve.
posted by odinsdream at 9:08 AM on March 29, 2005

I thought of it as a Venn Diagram Intersection (The shape made by two overlapping circles)
posted by kokogiak at 9:10 AM on March 29, 2005

I don't think Talbot's Curve is right, even though the shape hellbient is asking about is contained within it.

In jewelry, it'd be a marquise or a navette. In geometry, it might be a 2-sided Reuleaux Polygon, or digon. "Lenticular" (lens-shaped) might be an appropriate adjective.

Upon further snooping, it looks like it's just called a lens.
posted by bachelor#3 at 9:11 AM on March 29, 2005

In line with kokogiak and jessamyn's suggestions, here's a page that says the shape caused by two overlapping circles is a called vesica. It's a little bit down the page - just search the page for "vesica" or "football."

You can take the boy out of West Texas, but you can't take the West Texas out of the boy...
posted by Moondoggie at 9:24 AM on March 29, 2005

From Bachelor#3's link, "It is also known as the fish bladder or vesica piscis... Renaissance artists frequently surrounded images of Jesus with the vesica piscis."

It's the Jesus Fish!
posted by kokogiak at 9:27 AM on March 29, 2005

Running with Hidalgo's leaf idea, I stumbled across this page which calls the leaf of that shape elliptical. And I swear I found it looking for leaves and not footballs...
posted by Moondoggie at 9:29 AM on March 29, 2005

"All shield were made of cowhide, and were oval in shape, the big isihlangu type being slightly more pointed at either end than the umbumbuluzo." -- Ian Knight, Zulu, 1816-1906 (Warrior Series, No 14), ISBN 1855324741, page 20.
posted by profwhat at 10:03 AM on March 29, 2005

Like bachelor#3, I would say "lenticular" -- shaped like a biconvex lens. I use this term all the time to describe cross-section shapes and think it is pretty standard in the profession.
posted by Rumple at 11:47 AM on March 29, 2005

What would a Zulu call it?
Maybe you could translate its shape from that.
posted by thomcatspike at 1:21 PM on March 29, 2005

I like 'lenticular' and 'amygdaloid'. But I'd probably call it a pointed oval, myself.
posted by ikkyu2 at 4:06 AM on March 30, 2005