will this random terrain generator work?

[codingHere]

array (4,000) (4,000)

set each part of the array to one of the following:

rock
grass
air
dirt
water

this will make a mess.

so i will set the probability for each one at a different layer.
 
tell me if im wrong but this should probably work?

[G.]

It depends of your definition of "work" and since it's only a vague idea it will probably work