The 19th iteration of ProgDay, the world's oldest continuous festival for prog rock, should be called instead "Permutation Day." After all, the eight bands stretched over the two-day docket create unlikely stylistic hybrids. Saturday beginners Thank You Scientist, for instance, shoehorn funk and hard bop into mathematically minded hard rock, while Corima somehow manages to marry marching-band simplicity, heavy metal drums, samba and space rock into the endlessly restless songs of its Quetzalcoatl. From Iran, Mavara pits Iron Maiden-like thrall with icy electronica comedown. The weekend's strangest combination comes from its most intriguing band: Indonesia's simakDialog drifts into the same hazy ether of Miles Davis' electric period, but they weave the patter of hand drums endemic to their country and tides of rising-and-falling drone into that jazz torpor. After the ceaseless technicality of the bill's other bands, consider simakDialog a deserved exhalation.