"Quaternion is like the plague: it's fun at first but then all your descendants hate your guts for it. They're like complex numbers only they have three orthogonal imaginary axes instead of just one, and the group of unit quaternions is isomorphic to the R3 rotation group for whatever reason (quaternion multiplication = rotation composition, quaternion conjugation = rotation inversion, etc)."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.