Start this route from the right-hand side of the south face of the Lower Triangle (not on the ramp). You basically head up nebulous terrain for about 25 feet until you get to the obvious left-leaning hand crack. This crack peters out near the top of the triangle save for a little pod that allows some decent finger locks. The crux is pulling over onto the apex.
I ran this together with the Yellow Traverse to create a pitch Rossiter calls "Xanthomorphosis." Interestingly, he rates Xanthomorposis 5.10b S, but the Lower Triangle 9+ and the Yellow Traverse 9- VS (I guess the sum is greater than the parts in terms of difficulty, but not severity?). Personally I'd call the combination solid 5.9, and S for the potential ankle spraining/breaking falls that could occur on the Yellow Traverse if you blow the crux or the moves shortly thereafter.
Protection
I believe I used a 0.75 camalot, a #1 camalot, and a 0.5 camalot, in that order. Overall the pro is satisfactory and there's certainly room to place more than what I listed.
On second thought, perhaps "Xanthomorposis" gets it's difficulty rating when it's combined with "The Metamorphosis." Whatever - if you're climbing these climbs it's because you want to do "The Metamorphosis," "Scotch and Soda," or "Disguise," in which case Diffraction or King's X are much better approaches anyway.
Actually, the name is Lower Triagonal, which makes sense if you look at the feature.
By Tony Bubb From: Boulder, CO Sep 8, 2003 rating: 5.9+
The route can be [begun] one [of] several ways, but the best I found is by a 5.10 start on sloping feet and with a side-pull to a fingerlock in a pod, near the center of the S. Face, directly below a small pine growing on the ledge 25' up. This is probably 5.10a, S. As well, one can finish where the diagonal crack "peters out" either directly up (5.9+) or continue left past a closed section of the crack, along the end and around the corner- there are nice locks out there as well and it protects just fine (5.9+ too). Take a few fist-sized pcs for the diagonal crack.
One star. Ho-hum climbing because it is broken up and largely indistinct.
Seemed like 5.9+ anyway (5.10 start also possible) and was awkward/committing move, though the gear was good.