Consider a small workshop employing eight workers and specialized in manufacturing two types of products, starting from raw materials provided by customers. Several customers can order one of the two types of product in advance for the next month. Each customer orders his product through a phone call during which he specifies the date at which he can provide the corresponding raw materials. The manager of the workshop replies by either:

In the case where a delivery date is proposed, the customer can refuse the proposal. If the proposed date is accepted, it becomes a due date at which the manager commits to deliver the ordered product.

The workshop's workers are grouped into two teams, each dedicated to manufacturing one type of product. Inside each team, a worker specializes in one activity among the activities composing the manufacturing process of the corresponding product. Each activity takes one day to be performed and precedence constraints hold between the activities needed to build up a product.

The problem we are asked to solve is to determine the day by day timetable of each worker for the coming month, such that all promised products will be delivered on time and knowing that every five days in the month all workers have a two day break. The computed timetable will specify required working days for each worker.