How many sides of the triclinium are typically lined with couches?

A triclinium, which is a formal dining room in ancient Roman houses, typically features couches arranged along three sides of a rectangular space. This design allows for a communal dining experience where guests recline on the couches while enjoying their meal.

The arrangement of couches on three sides permits a central space for tables, enhancing the social aspect of dining. Guests would recline on their left side, using their right hand for eating, which aligns with the traditional Roman dining customs. By having couches on three sides, the triclinium creates an intimate setting, conducive to conversation and social interaction among diners. Thus, the correct answer accurately reflects this characteristic feature of Roman interior design.