In preferred form, {HEAD ~ the apparatus} includes a body having a groove with markings to define {TAIL ~ the display area} and a display bar that slidably fits within the groove 
In preferred form , { HEAD ~ the apparatus } includes a body having a groove with markings to define { TAIL ~ the display area } and a display bar that slidably fits within the groove
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH