What is this notation?
I have never seen this before, and I don't know how (or even IF) it can be entered into Musescore. I can do triplets not problem, and even the first one (in the red rectangle) where it has dotted notes. (Although I don't know why it's written as separate parts since it is four notes played together, in groups of three).
But the problem is the two triplets in the red circles. Here we have what looks like a triplet, but there are three number 3's over each one, with three dots below each number 3. I have no idea what this is, and have not been able to find anything about it online. I have been searching since yesterday. So if anyone has any idea what it is or how to enter it into Musescore, I would be very appreciative if you could explain, Thanks in advance.