A value driven by a particle's own age, t running 0 at birth to 1 at death. What a pair of endpoints cannot say: a smoke puff whose alpha falls fast and then lingers, a spark that shrinks by halves, anything that curves.
t
A value driven by a particle's own age,
trunning 0 at birth to 1 at death. What a pair of endpoints cannot say: a smoke puff whose alpha falls fast and then lingers, a spark that shrinks by halves, anything that curves.