There are 24 measures of cerdd dant in the ap Huw manuscript. Looking at them today, wondering what the various punctuation marks might mean - . and : and ) are used - I noticed something else. Many, but not all, of the measures have sub-elements that are 4 'digits' long. The ap Huw uses a binary tablature, with 0s and 1s corresponding to something like one measure of "away" or "home." So I've been practicing mak y mwn hir, 1111 0000 1010 1111 0000 1011, as six lines of four-bar melody. The actual melody is improvised, drawing on the "home" notes when there's a 1 and on "away" notes when there's a 0.*
*With two caveats: One, I don't think I've got the notes sorted correctly into "home" and "away" bins yet, according to the Bragod website anyway. Two, I definitely use the "home" or "away" note on the stressed notes of the measure, but maybe not on the unstressed. I use the "other team" as passing tones or such. Dunno if that's exactly right, but considering that a lot of the ap Huw ornaments sort of require it, I think I'm OK.
ANYWAY the point of the post is: Although there are 24 measures, if you look at the last four digits of each pattern, there are only 5 cadences in use:
That seems like a useful thing to know! Possibly also misleading - for example, while there is no 1001, there is a 10001. Looking only at the last four digits may not be the right call when universally applied. Still, I thought it was worth noting.