whereby said {HEAD ~ sign board} can selective produce visible light of only said first color, of only said {TAIL ~ second color}, or of both said colors by, respectively, exposing said first substrate surface, said second substrate surface, or both said substrate surfaces to ultraviolet light, thereby to produce said multi color visual effects, the light of said first, second, or both colors being visible when said sign board is viewed toward either of said surfaces of said substrate 
whereby said { HEAD ~ sign board } can selective produce visible light of only said first color , of only said { TAIL ~ second color } , or of both said colors by , respectively , exposing said first substrate surface , said second substrate surface , or both said substrate surfaces to ultraviolet light , thereby to produce said multi color visual effects , the light of said first , second , or both colors being visible when said sign board is viewed toward either of said surfaces of said substrate
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH