Visitor Pattern:
The visitor pattern is a behavioral pattern that provides a way of separating an algorithm from the object structure it operates on. This pattern is useful when you have a complex object structure and want to perform operations on the objects without contaminating their classes with these operations.

The Visitor pattern consists of:
1. Visitor:
Interface defining a visit operation for each type of "visitable" element.

2. Concrete Visitor:
Each implements different versions of the visit operations.

3. Element:
Interface that defines an accept operation that takes a visitor as an argument.

4. Concrete Element:
Each implements the accept operation.

5. Object Structure:
A collection of concrete elements.

Imagine you have a set of shape objects: a circle, a rectangle, and a triangle. You want to perform operations on these shapes, like calculating their area, perimeter, or drawing them. Instead of each shape defining all these operations, you can create visitor classes that visit each shape and perform their operations. This way, the shape classes remain focused on their attributes and don't get cluttered with functionalities.

Think of it like this: you own a large house with many rooms. Each room has different maintenance needs. You might need to clean the house, paint it, fix the plumbing, etc. You could hire specialists (Visitors): a cleaning crew, painters, plumbers, etc., to come to your house and visit each room, applying their expertise. The room objects don't need to know how to do all these operations, and they delegate these responsibilities to visitors who have the expertise.

Implementation in Go: