When the apparatus 100 is passed over a uneven variable surface such as a keyboard 10 as shown in FIG 5, each stem 112 extends under gravity so that {HEAD ~ both high and low points} of the surface are reached by {TAIL ~ the flexible tips} 116 
are reached by
When the apparatus 100 is passed over a uneven variable surface such as a keyboard 10 as shown in FIG 5 , each stem 112 extends under gravity so that { HEAD ~ both high and low points } of the surface are reached by { TAIL ~ the flexible tips } 116
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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH