Here we're going to mention the utilities of the func_*, target_* and trigger_* entities. Practical examples such as portals and teleporters are explained in the Creating dynamic features page. func_* entities have a wider variety of game purposes than other entity classes. They're sometimes represented by simple function boxes, though some of them are built out of brushes, patches and models. These constructions are sometimes called "b_models", though for many of them the word "mover" works as well, since they are made to be moving objects in the game world.