A more thorough explanation:

A common plan is the same as a common design. It refers to a plan or design that is shared by multiple people or groups. This plan or design is usually created with a specific goal in mind and is used to guide the actions of those involved.

For example, a group of friends may have a common plan to go on a road trip together. They would create a plan that includes the route they will take, the places they will stop, and the activities they will do along the way. This common plan helps to ensure that everyone is on the same page and that the trip runs smoothly.

Another example of a common plan is a business plan. A group of entrepreneurs may create a common plan for starting a new business. This plan would include details such as the products or services the business will offer, the target market, and the financial projections. This common plan helps to ensure that everyone involved in the business is working towards the same goals.

In both of these examples, the common plan is used to guide the actions of those involved and to ensure that everyone is working towards the same goals. Without a common plan, there may be confusion or disagreements about what should be done, which can lead to problems and delays.