Like input-output symbols, process boxes have a single line connecting it to the previous flowchart step and a single line leading to the next one. A flowchart may contain any number of process boxes.

Mechanical control systems (staplers, car windows) use parts for movement/force control. They include input, process, and output. Types of motion: linear, rotary, reciprocating, oscillating.

A flow chart, or flow diagram, ... It begins with the input of data or materials into the system and traces all the procedures needed to convert the input into its final output form.