Originally Posted by

**rintelen** THe reason why I asked this is that I saw this article by Max Tegmark. According to him 16 is the answer. I cannot imagine a physicist getting it wrong. I've copied below what he wrote. He also draws a diagram...not shown here. What am I missing from this description - in understanding - that gives him 16 arrangements? I don't get it.

EXAMPLE UNIVERSE

Imagine a two-dimensional universe with space for four particles.

Such a universe has 2^4, or 16, possible arrangements of matter.

If more than 16 of these universes exist, they must begin to

repeat. In this example, the distance to the nearest duplicate is

roughly four times the diameter of each universe.