[penagwin]

What? Rule 30 is on a 2D plane.

EDIT: Oh I understand now! Each generation is 1D. Thanks for explaining! :D

[kmote00]

Quote from previous link, in answer to a similar question comparing CAs (1d) to Conway's Life (2d):

"The pictures you're looking at, one of the axes is time. One row "becomes" the row below it. Each time-step iteration adds a row to the bottom, while the rows above it are immutable (because they are in the past)."

[seaish]

It's fundamentally 1D, with the vertical dimension used to illustrate how it evolves over time.

[pubby]

The universe is 1D. When you plot the universe over time you get a 2D image.