There was one other by the same author, for the beginning of Surat an-Naba, but he had to make up a weird exception to make it work. He said that the "عمّ" at the beginning of the Surah is really just short for "عما" so he gave the ا a two count. He isn't wrong that it's short for that, but he can't claim it's audially symetrric if that's not how any pronounces it.
Is this the first rhythmic structure that you’ve seen in the Quran?
There was one other by the same author, for the beginning of Surat an-Naba, but he had to make up a weird exception to make it work. He said that the "عمّ" at the beginning of the Surah is really just short for "عما" so he gave the ا a two count. He isn't wrong that it's short for that, but he can't claim it's audially symetrric if that's not how any pronounces it.