I have seen many representations in media of this tilaka where there is a tripundra over which an urdhva namam is drawn. it seems like what people not affiliated with a certain shaiva or vaishnava sect wear.
Also is there a particular tilaka that Indra worshippers wear?? As an adorer of Indra myself, what tilaka should I be wearing.
does the rigveda or yajurveda specify anything during the worship of indra of such intricacies? also are there any agamas that mention the worship of indra at home or anything related to indra temples?