O.V.I. namely Optical Variable Ink, when the printed optical variable ink pattern rotate from left to right,it will change from green to gold or the gold to green,the color can be divided into purple,red,blue,green,gold and so on.
O.V.I. yaani Optical Variable Wino, wakati muundo wa wino wa kubadilika uliochapishwa unapozunguka kutoka kushoto kwenda kulia, utabadilika kutoka kijani kibichi hadi dhahabu au dhahabu hadi kijani, rangi inaweza kugawanywa katika zambarau, nyekundu, bluu, kijani, dhahabu na kadhalika.