This locus may be, in various embodiments herein, a single pixel, a row of pixels, or a number of rows of {HEAD ~ pixels} of {TAIL ~ frame buffer memory} 
This locus may be , in various embodiments herein , a single pixel , a row of pixels , or a number of rows of { HEAD ~ pixels } of { TAIL ~ frame buffer memory }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL