I know that Havdalah candles are supposed to have multiple wicks, in order to form a "torch". My question is, to what extent do the flames generated from the wicks need to work together to form a stronger, torch-like flame? Do the flames need to join into one, or can they merely push against each other and make each other rise higher?
I've seen this happen with a double-wicked candle in which, it seems, the wicks are too far apart to share one flame, but the flames nevertheless interact and push each other higher and burn brighter. Not only that, but when one wick is lit, it will spread to the other (that's how close the wicks are), even though they will still not share the same flame.