Thus, when {TAIL ~ a viewer} views the exterior of the lamp generally in elevation, the cover selectively displays different designs to the viewer depending on {HEAD ~ the illumination state} of the device 
Thus , when { TAIL ~ a viewer } views the exterior of the lamp generally in elevation , the cover selectively displays different designs to the viewer depending on { HEAD ~ the illumination state } of the device
OTH OTH OTH 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH