Yep...every part is identical. In fact, the way they're designed, they're not only interchangable, but can be stacked to reduce volume for transport.
In fairness, a few parts in this dome had to be different. They had to "cut" the lower pieces, to give it a flat bottom...in a full sphere, all the pieces are completely identical.
Here's the easiest way to explain it. Got a soccer ball? Good. A soccer ball can be analyzed as a truncated icosahedron...every part is a regular pentagon or regular hexagon, and they follow a very rigid pattern.
Soccer ball graphic:
Now, look at every "corner" on the ball...where a pentagon and a hexagon meet. There are 3 edges...one pentagon and 2 hexagons...those are the 3 edges in this fly's eye dome. They describe angles of 108, 120, and 120 degrees. (This is 3 dimensional, not planar geometry, so they don't have to add up to only 360) Notice in the picture linked above, that there are 3 legs to each piece...2 are thin, and one is thick. That's the geometry it reproduces...the edges of 2 hexagons and a pentagon. 6 components around a circular window make a hexagon...5 around a window make a pentagon.
Ingenious, isn't it? And pretty, to boot!
Here's a picture of it going up, piece by piece. It's about a 20-25 foot diameter dome...fairly small, but sufficient for a small home. You can see the component parts in the picture, as well as their relationship to the people erecting the dome. Domeraisings are like Amish barnraisings...lots of people around, to help.
-- Chuck Knight
P.S. Don't even get me started with tensegrities...floating rigid members, suspended in a tensile web of string, and with no rigid parts touching each other. They're all suspended in a web of string, and tensioned by each other, without touching.
Seriously...it'll give you a headache, trying to figure it out.
