The Brickworks boosts clay production in the village. At Level 1 it adds 5% to your base production, and at subsequent levels 5% more to a total of 25%. Note that the Brickworks bonus does not apply to other bonus effects such as Oasis income or the 10% PLUS bonus. There are also villages consisting of three or five clay fields. The more fields in a village, the earlier the Brickyard levels can be efficiently constructed. For four field calculations, see Field Efficiency