Bi/Quadruped locomotion vs an Odd number of Feet

[TBerk]

Pierson's Puppeteers have a triangle shaped 'pelvis', one w/ two front
limbs and a rear one, all adorned w/ hooves on the end. (They are herd
like herbivorous.)

http://en.wikipedia.org/wiki/Pierson%27s_Puppeteers

I'd been thinking of a different species, on with an odd number of
limbs as well.

I'd also remembered in the Smoke Ring world the indigenous life-forms
seemed to also be triad based, tripodal and/or 'power of threes' or
something.

I'm thinking there'd be some pros and cons to not having an even
number of 'stuff'.

berk

[cavelamb]

I think the Moties had a third arm.
from "The Mote In God's Eye"
Niven and Pournelle