When {HEAD ~ the operating unit} is at {TAIL ~ a stored position}, the second shafts of the operating unit is moved from the front side of a mobile phone to the back side thereof, so that the operating unit is closely attached to the back surface of the mobile phone 
is at
When { HEAD ~ the operating unit } is at { TAIL ~ a stored position } , the second shafts of the operating unit is moved from the front side of a mobile phone to the back side thereof , so that the operating unit is closely attached to the back surface of the mobile phone
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH