Here is my x-module arch. One of the design challenges was to make it sit flat on the ground. I also designed it so it has 180° rotational symmetry about its apex. This is aesthetically pleasing and it also aids construction: I assembled it as two identical separate structures until I got to the apex x-module. The experience with the Eight-Stage X-Module Torus was helpful when I did the design since I learned there the effect of various weighting schemes on the curvature of an X-Module column. And starting the assembly of the structure was helped by having the Two-Stage X-Module Column in hand.
The X-Module arch is ethereal without being chunky. The motley color scheme I gave it disguises its X-Module origins somewhat and also highlights some interesting strut groupings. As compared with the Eight-stage Tensegrity Arch, it is easier to assemble per unit of arch length since it has one less strut and several less tendons per stage, although I don't think I could get the rainbow effect with this two-fold arch that I got with that three-fold one.
This arch is also omni-triangulated which Kenneth Snelson puts a lot of stock in. I find that attitude more appropriate to engineering than art. Sometimes I think wobbliness is a very appropriate attribute of a work of art or an acceptable side effect on aesthetic grounds, and there are even engineering structures where wobbliness is desireable. In any case, he also has an X-Module arch.
One of the reasons I chose the eleven-stage design was that I wanted the apex X-Module to be in a verticle orientation. Arches based on 3, 7, 11, 15, ... stages allow this. An "x marks the spot" sort of arch (speaking from an aerial point of view) would be obtained using a 5, 9, 13, 17, ... stage arch. Even-stage X-module arches are also a possibility, but with those the challenge of getting a stable base is much greater to say nothing of leveling it.
I completed assembling this structure on April 2, 2004. For assembly information, see the datasheet. This model is available on the Tensegrity Viewer as "X-Module Arch" and as a VRML model.