I’m trying to remember the title of a book I once read that was set in a 2-dimensional universe. It wasn’t Flatland (though I’ve read that one, too). The universe was sort of sliced vertically, rather than horizontally as in Flatland, and tried to explain realistically how life in such a universe could work. The basic plot was about some computer programmers that somehow managed to contact a creature from this universe and follow him around as he explained things. I read it when I was taking Physics in High School, so it must have been written before 1990.
Any ideas what book this could be?