Since we are all concerned with php2shell patch, let me share the fact that, like bugs, "patch for software" is also not a metaphor. You know that ancient computers ran on punched paper tape and cards with one hole per bit of instruction. If the code had an error, programmers had to physically cut out the flawed section, cover the hole pattern with a scrap of paper, and re-punch the correct code onto it. This patched piece of paper is where the term "software patch" originates. We still apply patches, just not on paper but hundreds or perhaps thousands of endpoints.