Projection

Projection is the ability for Cylon agents to visualize a synthetic environment around themselves.

Projection, as Caprica-Six calls it, is used by Cylons to easily make their way through the otherwise confusingly identical corridors of a basestar.

This ability is called into question by Gaius Baltar, who strongly believes that he has been projecting a virtual Number Six (in the form of a doppelganger of Caprica-Six) as well as assorted comfortable environments, such as a beach or Baltar's former home on Caprica ("33,"", et al.).

Baltar, as a result of this information and the fact that only seven of the twelve Cylon agents are in use on a basestar, leads him to suspect that he, is one of the final five Cylons (Torn).

Baltar (or his virtual Number Six) apparently projects he and virtual Six on a beach, and have sexual intercourse in order to block or distract Baltar from the effects of torture inflicted by Number Three for his omission in reporting a dangerous beacon found near the Lion's Head Nebula (A Measure of Salvation).