Second-order Cellular Automaton definition What does second-order term mean in a Cellular Automaton?
I read on second-order cellular automaton (wikipedia) that a second-order has two time-states, but does the definition of an order mean the number of time-variables that the function $f$ maps onto?
If we have two cells at time $t-1$ instead of three, and one cell at $t-2$, this is not a second-order cellular automaton? if yes, why is this so? It says all second order are reversible.
I ask because there are tons of ways to construct an Cellular Automaton, and therefore it is nice to know which terminology to use when describing the automaton.

Second order cellular automaton relay also on the layer at $t-2$ for pattern computation.
As "neighborhood" in Second order term is the cell at the step $t -2$ respect the present state of the cell in $t -1$, and on those information will derive the final outcome of the same cell at $t+0$.
