You should totally make a multiplayer version where you could wash other peoples stones and see how they have progressed. Oh you could call it "Rock Quarry" People could even pay to have their stone relocated closer to friends stones!!!
well, there's Sim Stone 2 I developed a little while ago, it will be more advanced and multiplayer is in development right now, but it will be more in MOBA direction than social, so you will be faced with one other random player against two random enemy players and you will be throwing your stones at each other, there's shop with items that will make your stone stronger in various ways, etcetc. now it's very basic, but time will show :)
cheers, it's fun to watch people still take interest in this one, as it is very old...