Brick (term)
From MediaWiki

A brick is a fan term, usually derogatory, to describe a toy that has particularly low articulation. Most examples of bricks tend to be smaller toys that have been given limited articulation to keep costs down. The Throttlebots and the Duocons are prime examples. Some larger toys, such as Powermaster Optimus Prime, can also be described in this way however.
Due to the limitations of the toy technology of the time this is something that usually refers to G1 toys, however some more modern toys such as Armada Super Optimus Prime suffer from the same problem.

