:wiggles: n. [scientific computation] In solving partial differential
equations by finite difference and similar methods, wiggles are
sawtooth (up-down-up-down) oscillations at the shortest wavelength
representable on the grid. If an algorithm is unstable, this is
often the most unstable waveform, so it grows to dominate the
solution. Alternatively, stable (though inaccurate) wiggles can be
generated near a discontinuity by a Gibbs phenomenon.
-- The AI Hackers Dictionary