The Golden Toad, the latest work by the experimental troupe the Talking Band, is a long, often amusing journey of discovery, but its characters do most of the discovering. The audience eventually learns everybody’s back story and who connects to whom, but not much about what it would be like to be any of these people. Watching the show, an elaborate construction in which the audience changes theaters four times, is like doing a jigsaw puzzle with friends: Eventually, the pieces fit together, and you see a picture, but the real rewards are presumably found along the way. Certainly the group, celebrating its 40th year with this production, gives you a lot to see and hear on the trip. The piece is told in four episodes and a short epilogue, the audience hoofing to a new part of La MaMa’s rather large space for each segment. First is an apartment building in Brooklyn, where it’s 2009, and Valerie (Ellen Maddow, a founder of the Talking Band) is having some trouble with her upstairs neighbors. They’re a gay couple (Mikeah Ernest Jennings and James Tigger! Ferguson) who are raising a daughter, Ava (Helen Gutowski, the standout in this cast). The next three hours are occupied by what happens to these and other characters in the ensuing years and the unexpected ways their lives intertwine.