Idunno is there such a thing as two-dimensional culture? ...counting down until the know-it-alls appear... Depends what you mean. Agar plates used to cultivate bacteria are planes, so this would be an example of a "two-dimensional culture". Of course, there is a volume of agam, as the agar has a depth. But that is not what is meant. And we all live in multi-dimensions, but are unable to apprehend the true scale and scope of these. Go read
Flatland (Good lord, I'm back in high school. I'm thinking of a book I read for Sophomore Geometry and the Advanced Biology I took senior year. Over lunch, I read an article written by the still hotter older-sister of my Junior-year gf)