Yes, Burmese climbing rhyme is interesting and Vietnamese Luc-Baht even more so, but the Ewart verse isn't either of them. I wonder where he got it from, or whether he made it up. I wish he were alive to tell us.

Look at the stanzaic rhyme schemes for "The Star-Spangled Banner," "The Cremation of Sam McGee," or "The Raven." If internal rhyme is used schematically it has to be annotated, though I'm not sure I've ever seen a single way of annotating it.