Made by the same director, it has a very similar style of editing, cinematography/lighting and overall atmosphere. Both have animated elements integrated with live-action too, and they even share a part of the OST. Why R U is referenced a lot through YYY, and Porpla is a fan of the series and SaifahZon shipper. Both series have playful, wholesome couples. YYY is at a higher level of 'crack energy' though, but Why R U is also more 'crack' than your average BL series.