After Athens buzz band Reptar went on indefinite hiatus a few years back, two of its members, Andrew McFarland and Ryan Engelberger, branched off as Semicircle and released an understated stunner of an LP in 2014’s Blown Breeze, Grown Grass and We Are Part of the Earth. Now, Engelberger has embarked on another creative path as Curt Castle, which will celebrate the release of its first recorded material—a 7-inch single—Friday at the Caledonia. The lead track, “Afraid of the Lightning,” is a punchy pop tune that should please fans of ’70s-soft-rock stans like Stephen Steinbrink. The B-side, “Across State Lines (Supernova),” is a Casio-hued slow-burner that bodes well for the inevitable upcoming full-length.