A piano keyboard rendered as a colorful SVG interface lets users play notes by clicking keys, with each key displaying its corresponding solfège number. The React app maps 24 notes to specific frequencies and uses the Web Audio API’s `OscillatorNode` and `GainNode` to generate short sine-wave tones. Each white key is filled with a pastel rainbow color based on its note letter, while pressed keys temporarily brighten or darken. The layout includes both white and black keys, with black keys positioned between the white ones at higher vertical offsets.