Portal wall.

Idea: Why not make portal 'block' behave like a regular glass, wall and fences that can only stick to obsidian or to each other. I made this suggestion basically because of cosmetic purposes but it seems logical plus it enables us to make crossed portals. Crossed or rather joined portals behave as one portal. (By that i mean that a crossed portal in the overworld is considered one and can be simply linked to a corresponding portal in the nether. This must also work in reverse.)