One thing they taught us in cooking school that I never really understood, but follow nevertheless, is to serve things in odd numbers. Think about it: there are usually three shrimp in a shrimp cocktail, or something is cut in wedges (triangles), or an item is plated off-center to create an unbalanced look. Even Artie grows buds in odd numbers.
Maybe symmetry is considered boring. Maybe round is too easy. Whatever it is, I do tend to serve things in odd numbers now when creating a look. But when it's just me, I usually end up with an even number of whatever. I don't exactly have a fear of odd or prime numbers, but the lack of symmetry makes me uneasy. That may be the point. Put diners off guard by creating something that upsets expectations. I'm not all that into food as art, but that's what really expensive restaurants specialize in.
Just remember that the point of a presentation is to make the food more appetizing. And also that you're feeding someone, so don't make it so weird that they don't want to eat.