Block comments can greatly enhance the readability and maintainability of Matlab programs. They allow programmers to document their code with explanations, instructions, and meta-information which is essential for understanding the operation and structure of the program. Comment blocks are an intrinsic part of good coding practices and software engineering principles.

Having good documentation through block comments directly addresses the problem of software maintainability. In complex software systems, written using Matlab or any other language, understanding the codebase is often time-consuming and error-prone. Block comments offer a solution to this problem.

## Code for Block Comments in Matlab

The use of block comments in Matlab is simple and straightforward. The syntax of block comments in Matlab is as follows:

%{ This is a block of comment in Matlab. Anything enclosed in this block is considered a comment. %}

**Note:** Everything between the %{ and %} is considered a comment in Matlab.

Above, the %{ and %} tags are used to start and end a block of comment. Any text within these tags is not executed by the Matlab interpreter and it is mainly for the programmer’s reference.

## Explanation of the Code

Block comments in Matlab start with the %{ symbol and end with the %} symbol. This block of comment can span multiple lines, and Matlab’s interpreter ignores everything within this block. This is useful to comment out large blocks of code or to provide multiline comments.

This is best understood with an example. Consider the following piece of code:

%{ Determine the roots of a quadratic equation ax^2 + bx + c %} a = 1; b = -3; c = 2; discriminant = b^2 - 4*a*c; root1 = (-b + sqrt(discriminant)) / (2*a); root2 = (-b - sqrt(discriminant)) / (2*a);

In the example above, a block comment is used to describe what the code does. It notifies users or other programmers that the script is for solving a quadratic equation of the form ax^2 + bx + c.

## Importance of Matlab Library Functions

Matlab also provides **library functions** that aid in documentation. For instance, the HELP function provides comments and syntax for any function when used and the DOC function presents the formatted help text in the Help browser, providing a well-documented context.

Using block comments efficiently and effectively along with these library functions can make a tremendous impact in understanding the functionality of the code, enhancing the software maintainability, and correspondingly reducing the software’s lifecycle cost. Now, isn’t that fashionable in the field of programming?

## The Art of Combining Comments and Code

Just as different pieces of clothing are combined in fashion to create desired looks, comments and code in programming are also mixed to enhance code readability. The key is knowing when, where, and how to best use these comments. The ethos of this practice is very similar to the theory in fashion: every item has its place and purpose.

In commenting as in fashion, the rule of thumb lies in understanding the audience. A well-dressed piece of code is as pleasing to its readers as a well-dressed person is to the beholders.

## History and Evolution of Comments in Programming

Comments in programming have a history that parallels the evolution of programming languages themselves. Early programming languages didn’t have the concept of comments. As languages evolved, so did the need for code documentation – giving birth to the use of comments.

Matlab, owing to its root in the academic world, understands this ethos and has always promoted code documentation and commenting right from its inception in the late 1970s. This history has helped in shaping the habits of Matlab programmers worldwide – making Matlab code among the most readable and maintainable.

In conclusion, block comments along with Matlab’s inbuilt documentation aids, greatly enhance the process of code understanding and maintenance. They are like the detailed fashion notes from a designer, provided with each creation, to allow the best and most appropriate use of the design.