Add categories for sounds, e.g. water, fireplace, animals (birds, ...) and the possibility to create themes this way

YES, & MAKE NATURE SOUNDS OVERLAPPABLE... IE: A BROOK,OR CREEK, IN THE FOREGROUND; WITH, THE ABLITY TO ADD, (TOTHE 'PLAYBACK'..) TWO, OR THREE OTHER, SOUND FILES, (DEFAULT TO ONLY SOUND FILES THAT ARE PRE-LOADED ON YOUR ACHINE) OR, USE GENERALLY AVAILABLE SOUND FILE TYPES. (IE: *.WAV, OR *.MP3, FILES.)
IF THS IS MADE AVAILABLE, I SUPPOSE, BIRD SONGS, CHIRPING, NEARBY COULD BE ADDED, (OR, SUPERIMPOSED OVER, THE CREEK, SOUNDFILE).... BUT BE CAREFUL TO AVOID OVERLAPPING OF THE SOUNDS... BY MAKING THE FILE, TOO SHORT OF A SAMPLE; & THE USER CAN HEAR, 'REPLAYS'. OF CERTAIN SOUND REPITITIONS... AVOID THIS BY MAKING THE 'SOURCE' SOUND FILE, REARRAINGEABLE... WITHIN ITSELF !!
OR WAVES, COMING TO SHORE... WITH; (NOW, THIS IS TRICKY..) AN OCCAISIONAL SEA GULL, IN THE DSTANCE.. BUT THE GULL, CANNOT REPEAT ITSELF !
NOTHING IS MORE IRITATING, THAN A "WAVE SOUNDS" GENERATOR, THAT'S REPEATING ITSELF. ..