What is the verb for dividing something into regions?

Imagine a piece of paper on which you can draw some "regions". What do you call this act?

These words can probably better tell you what I mean, but I know they don't exist in English:

• Regionize: I regionized the paper
• Enregion: I enregioned the paper
• Region itself as a verb(?): I regioned the paper

In reality, I am a programmer "enregioning" a skin. I would be happier if the verb had clear relation with "region", because that is the technical term I am using for those parts of the skin. That way, the "enregioner" would both have a meaningful name and one that makes users understand it is creating "regions"

The verb I would use is regionalize. This would not refer to a "paper" partitioning, but rather dividing a country on a map for the purposes of say, marketing.

You may use

I partitioned the paper.

or

I divided the paper (into segments, sections, regions, etc.)

You could partition the item into partitions.

You could segment the item into segments.

You could divide the item into divisions.

You could apportion into portions.

I would personally use demarcate, I think it's probably closer to what you are looking for

In the context of computer graphics and modeling, terms like mesh generation, mesh triangulation , triangulation, and optimal triangulation are frequently used, and grid generation occasionally. If all the regions on your paper are triangles, triangulation would be a good choice.