Under the Radar is agreeably difficult. Entries in the new play festival, hosted by the Public Theater since 2006, invariably upend convention, but they also avoid the pretentiousness that often sinks experimental work. Boundaries were certainly broken in the fest’s fourth season, which wrapped Jan. 20, but as audiences were pulled in new directions, they were also given accessible anchors.Those touches — familiar devices, likeable characters — are crucial, because they help everyone expand their theatrical horizons, not just the adventurous fringe. Superficially, for instance, Mark O’Rowe’s “Terminus” seems cliche. It’s yet another Irish drama about dysfunctional poor people, told as a series of interwoven monologues. There’s a mother (Andrea Irvine) estranged from her daughter (Eileen Walsh), and there’s a violent bloke (Aidan Kelly) who forces them to reconnect. But there’s also rhyme. O’Rowe writes the entire piece in verse, and he’s not interested in cutesy couplets. Complex rhythms tumble from the script, rhyming blunt obscenities with elegant turns of phrase. The language evokes such rich images that the empty set — just black walls and hanging shards of mirror — becomes the perfect counterpoint. And though the actors communicate the sense of their lines, they also submit to the sound of them. Guided by O’Rowe’s direction, they sway their bodies or flick their heads to the consonant-vowel interplay. The effect is hypnotizing. The language sounds otherworldly, and that’s the ideal state for the play’s bizarre turns. As pure realism explodes into a tale of demons and angels, the verse makes supernatural elements easy to embrace. Two other shows — Young Jean Lee’s “Church” and “Poetics (A Ballet Brut),” created by Nature Theater of Oklahoma — use human bodies to suddenly change their scope. “Church” creates a religious revival, complete with preachers, prayers and a joyful dance. The theatrical performance of actual spiritual rituals has had a mini-boom, but unlike Les Freres Corbusier’s “Hell House,” which staged a “haunted house of sin” originally created by Evangelicals, Lee’s play doesn’t let us off the hook with smug irony. Her preachers may be characters, but their sermons on the spiritual bankruptcy of well-meaning urban liberals (read: theatergoers) sound awfully sincere. There’s value in staging faith without sarcasm. It lets us consider how the tropes of theater mirror the tropes of church, suggesting that both have the power to heal. This point is especially clear when one minister (Brian Bickerstaff) starts talking about mummies with the same conviction he used to admonish our souls. Even if you don’t believe the words, the play asks, isn’t there something moving about watching a heartfelt testimony? And isn’t there something religious about an enormous cast creating a community onstage? The unexpected finale, which involves more than 50 people, says the answer is yes. It’s not explicitly religious, but “Poetics,” a largely wordless dance piece, makes a similar case. It begins with four scruffy hipsters in thrift-store clothes standing around in awkward silence, sucking drinks from straws or making furtive eye contact. As they slowly start mimicking each other’s movements, their looks of frustration tell us they’re trying to communicate. It’s a thrill when the soundtrack of 1970s and ’80s tunes kicks in and the troupe finds a common physical language. The choreography gets increasingly more complicated, and a vague story emerges about romantic entanglements. Of course, watching ragamuffins dance like pros has been funny since electronic artist Fatboy Slim released his musicvideo for “Praise You,” but “Poetics'” true joy comes when the back curtain opens. The audience, seated onstage, sees into the house. A massive crowd joins the four stars in a routine, and for a moment, the show celebrates how we can all be connected. At 70 minutes, the piece often gets repetitive, but the joyous payoff is worth the unusual journey. Unusual on a smaller scale, “Etiquette,” from U.K. troupe Rotozaza, forces us to see the theater in our daily lives. Staged in a diner near the Public Theater, the show involves only two audience members, who each put on a set of headphones and follow prerecorded instructions. There’s a lot to do in 30 minutes, what with all the props to be used and lines to be spoken, and the piece is often as disorienting as it is illuminating. However, it’s also weird and fun, and it invites participants to realize how we limit ourselves by treating our lives like they’re scripted. In her solo performance piece “Low: Meditations Trilogy Part I,” activist-writer Rha Goddess fights to change our perception of the mentally ill. Through rap, song and spoken word, she tells the story of a young woman, nicknamed Low, whose severe disorders unravel her life. A bracing performer, Rha Goddess laces her political arguments with enough human detail to make them moving. Low’s break with her family, her descent into homelessness and her palpable fear of New York’s county hospitals are even more upsetting because we’ve gotten to know her so well. Even when she’s at her worst, the writer-performer won’t let us forget that this character once had “normal” concerns about boys and homework. Like so much of Under the Radar, Low is powerful because she’s both recognizable and strange.