This has been bugging me for a while.
I've noticed that cutie marks always seem to maintain their orientation relative to which way the pony is facing. For example, look at Twilight's cutie mark - one large star surrounded by five smaller ones. Out of the five smaller stars, three are always closer to her head than the large star, while two are always closer to her tail, regardless of which way she's facing.
The same seems to apply to all ponies. In Trixie's cutie mark, the opening in the crescent moon faces her head, no matter if you're looking at her left cutie mark or her right one. Fluttershy - the butterfly closest to her head slants towards her head, the other two slant towards her tail, again on both flanks.
Vinyl's cutie mark, however, has me curious. On her left flank, her cutie mark is a standard musical note, with the heads of the note to the left of the stems (facing towards her head). However, we've yet to see her cutie mark on her right flank, and I can't help but wonder what it looks like.
On one hoof, based on every other cutie mark we've seen, you'd think that her cutie mark would be reversed - the heads in the musical note to the right of the stems - so that the shape of the cutie mark will maintain orientation towards the direction she is facing, like every other pony. However, if that happens, then the cutie mark on her right flank would not be a musical note anymore, as they don't face that way.
On the other hoof, if the heads of the note remain to the left of the stems on her right flank, it would still be a valid musical note, but at the same time, it would contradict the way every other cutie mark is mirrored.
So with that in mind, which way do you think her right cutie mark faces?