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