https://phys.org/news/2018-06-clone-warsfinding-buggy-code.html

It is common practice for software developers to copy, paste and modify a fragment of existing code to suit the task or tool they are working on. This is called cloning, and the resulting code from the copy-and-paste process is, of course, called a clone.

"There are valid reasons why cloning is so common," said Roy, whose research is supported by a Natural Sciences and Engineering Research Council of Canada Accelerator Grant. "It saves time, there is low risk in using stable code, and it results in faster development. There is no need to reinvent the wheel."