Tones is a "web instrument" with 8 musical notes that change randomly with each page load.
Tones uses dynamically created WAV files and data URIs to generate 8 random tones for each page load. Unfortunately, this technique is not supported by all modern browsers. Notably, the browser in iOS 7 does not support data URIs for the audio element. Support for this accross other modern platforms seems reasonable (desktop browsers, Chrome on Android).