In memory of the man who put red and green squiggles under words

Tony Krueger, a longtime Microsoft Word developer who worked on multiple versions of the software, passed away recently. He is best known for creating the real-time spell-check feature that displays red squiggles under misspelled words and green squiggles under grammatical errors—a feature now standard across nearly all word processors. His innovation transformed spell-checking from an intrusive, blocking operation into an unobtrusive background function that has become ubiquitous in digital writing tools.