Instrumental only. Solo felt piano ONLY. One instrument only. Monophonic single-note melody only. No chords, no arpeggios, no harmony, no layered sounds, no accompaniment of any kind.
Hard restriction: only felt piano is allowed to produce sound.
Explicitly forbid all other instruments and timbres:
no violin, no viola, no cello, no double bass, no strings, no string ensemble, no orchestral sounds, no bowed instruments, no cinematic layers.
no flute, no shakuhachi, no recorder, no wind instruments, no brass.
no pads, no synths, no ambient layers.
no guitar, no harp, no bells, no mallet instruments.
no background textures.
Tempo 58 BPM. Very sparse spacing between notes. Soft velocity, muted attack, dark warm tone. Minimal short room reverb only. Loop-friendly structure for sleep/relax background use.