Change lighting, change much.

Creeturs Room alt 2

The pattern of the room is a square 2D image created in PhotoShop (image editing software) and mapped to the 3D surface. The textured look, of depth or bumpiness, is due to the amount of normal effect selected. Very briefly, a vertex's normal can be depicted as an arrow pointing directly away from that vertex point so increasing it increases the distance from the point and thus adds an element of thickness.