LilyPond is a computer program for music engraving that produces high-quality sheet music from plain text input. Users write musical content using a markup language describing pitches, rhythms, articulations, and layout rules. The software processes the text file and generates graphical output in PDF, SVG, PNG, and MIDI formats. LilyPond follows the WYSIWYM paradigm (What You See Is What You Mean), similar to LaTeX, applying traditional engraving rules from the era when scores were engraved by hand.