Abstract Tribe Unique, Friday, April 12, at the Boulder Theater, slowly crept into the public's awareness in 1995, when it joined the select roster of Grand Royal Records, the Beastie Boys' nearly mythic imprint. Since then, the crew has dropped three albums on Battle Axe Records and continues to hone its performance style -- a fierce amalgam of beats, breakdancing and the emcee work of Abstract Rude. The Tribe is now the centerpiece of the Flow & Tell tour, a sort of dream team of underground hip-hop that comes to Boulder courtesy of Radio 1190's Basementalism, the hippest bit of hip-hop radio this side of the Continental Divide. The lineup also includes 2Mex (of the Visionaries and OMD), Awol One (of the Shapeshifters/Massmen), Bus Driver (of the Afterlife and Project Blowed) Canada's Swollen Members (pictured) and the Bay Area's DJ D (of the Massmen) and Bukue 1. Nothing is going to stop this flow.