The Jacquard loom greatly simplifies the process of weaving complex, figured designs. In a figured design, warp ends must be operated individually (either raised or lowered) to create complicated shapes and forms.
Jacquard looms contain a Jacquard "head" which mechanically controls the raising and lowering of specific warp threads in a given pattern. Before Jacquard looms, this selection was done by an actual person, called a draw boy. Draw boys sat inside the loom, physically moving the warp ends as instructed by the master weaver, who sat in front of the loom and passed the shuttle.
Jacquard looms not only cut time and labor but also enabled weavers to recreate the same design over and over through the use of cards. In Jacquard weaving, punched cards are read by the loom, and indicate which warp threads need to be raised/lowered in a given pattern. On the cards, each row of holes represents one weft shot (or row) within the design. As the cards pass through the Jacquard "head," they are met by a series of small needles, each of which is connected to a hook. Whether the hook raises or lowers the corresponding warp thread is dependent on the needles meeting a hole or a blank. Cards can be stored, and brought out again whenever the design is to be reproduced.