Soft 50 ms pink-noise bursts over the base noise — rain finding a rhythm rather than a metronome. The shape comes from a 2026 MIT sleep study, where bursts like these, timed by live EEG to the peaks of slow waves, enlarged those waves. The timing was the whole point: the same line of work finds bursts that miss the peak do nothing. A web page cannot read EEG, so this is texture, not that protocol, and it makes no claim on your sleep.