Answer: VISUAL CONTROLs are placed in plain sight for all employees.
Explanation: In the context of lean tools which are means used in management to get the most out of every resources, improve productivity and efficiency, visual controls are used to communicate by using things that can be seen. A graphic, images, pictures, etc. Examples are stop signs, coloured clothing, etc.
These designs permits quick recognition of the information being communicated, in order to increase efficiency and clarity.