{HEAD ~ The vibration device} 24, wherein a change in the direction of the combined vibration force corresponds to a change in the direction of a simulated motion in {TAIL ~ the computer simulation} 
{ HEAD ~ The vibration device } 24 , wherein a change in the direction of the combined vibration force corresponds to a change in the direction of a simulated motion in { TAIL ~ the computer simulation }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL