Los Angeles’ Grave Flowers Bongo Band’s sophomore LP “Strength of Spring” is an inverted pyramid balanced on the headstock of an acoustic guitar, a rainbow painted in campfire smoke, an endless staircase circling into the clouds. That acoustic guitar, perfectly captured here by Ty Segall’s excellently sere and close mic’d production, plays skeleton to these conjurors’ woolly grooves, and singer Gabe Flores’ thousand-yard moan keeps us guessing as to exactly where this wildebeest is headed.