A special case of biological pattern formation is the emergence of pigment pattern on the shells of mollusks. The shells consist of calcified material. The animals can increase the size of their shells only by accretion of new material along a marginal zone, the growing edge of the shell. In most species, pigment becomes incorporated during growth at the edge. In these cases, the formation of these patterns is a one-dimensional process. The second dimension is a protocol of what happens as a function of time. The shell is, so to say, a space-time plot.
For more details see e.g.
H. Meinhardt
Biological pattern formation as a complex dynamic phenomenon,
Int. J. of Bifurcation and Chaos 7, 1, 1-26 (1997)