A “phantogram” is an optical illusion in which a two-dimensional image appears three-dimensional — through precise design, a simple confluence of line and shade can almost physically leap off the page. Before I went to see Phantogram play the Paradise last Sunday,

I think I thought of them rather two-dimensionally, as a smoothly produced electro-pop band that blended seamlessly with so many other groups in my mind. By their set’s end, though, Phantogram was really leaping off the page. I realize now that they’re really one of the better bands on the scene right now, and their new self-titled EP is a signal of seriously interesting music still to come.

It’s always a little uncanny when, seeing a band for the first time, you realize what it takes to make the kind of sound you’re familiar with coming from them. Phantogram’s instrumental lineup is simple — Barthel on keys and vocals, Carter on guitar and vocals, and Chris Carhart on drums— but the sound they produce is much bigger  and more hypnotic than its simple rock band setup would suggest. Barthel is like an updated Karen O in her sharp femininity, dressed to kill in a torn black-and-white blazer and sky-high glittery gold boots, a curtain of black hair hovering above her collarbones. She plays the keys with vigorous enthusiasm and power as she sings, angelic and secret-agent smooth. Carter’s guitar sound is urgent and confident, dark and high-impact, and sings with a voice a bit like a young Sting’s, only richer. Bass drops throughout the set were satisfyingly deep and tight, especially with perennial favorite and final song “When I’m Small,” a bad-ass anthem perfect for stomping down city streets or zooming through a freeway in a Bugatti.

Josh Carter and Sara Barthel, the band’s two constant members, have known each other since their high school days in upstate New York, and have been playing together (first as Charlie Everywhere and then as Phantogram) since 2007. They burst into the wider scene with their first album, Eyelid Moves, in 2009, and have since put out four EPs. They’re working on their second full-length studio album, Voices, now, and Sunday’s set included previews of a few exciting new tracks. “We’re not technically supposed to play this…” Barthel disclosed, grinning, before launching into “Howling at the Moon,” a banger from the upcoming record, and I almost wish they hadn’t, because now it’s all that I want to listen to, and I can’t yet. Other standout numbers included “Black Out Days,” a howler off the new EP, and old favorite “Don’t Move.

When they left the stage, a thundering rush of applause swept the audience, louder than I’m used to, and more joyful. It became very clear to me that this is a band with adoring fans, people who’ve seen this band play over and over again for years. Barthel and Carter returned to the stage for a gorgeous three-song encore, ending epically with Eyelid Moves‘  harrowing “Futuristic Casket” and a few heartfelt words for the city of Boston when the applause finally quieted, where they first played in 2009 at the Great Scott, a memory they still hold dear. It was heartwarming to see such a peculiar, sweet reunion.

In the days following the show, Phantogram has been pretty much all I want to hear, all day, every day. I think it took seeing them live to understand their persistent appeal, versatile and satisfying.  I can’t wait to hear the rest of Voices, but in the meantime, I’ll cycle through the rest of their records and await the sweet day when I can see Sara Barthel beat the crap out her keyboard once again.