Historical Rules · 28 April 2017
Rule 712.2
Official source text from the 28 April 2017 Rules release
One card in each meld pair has an ability that exiles both that object and its counterpart and melds them. To meld the two cards in a meld pair, put them onto the battlefield with their back faces up and combined (see rule 701.35, “Meld”). The resulting permanent is a single object represented by two cards.