Some filmmakers spend tens of millions of dollars to create the kind of elegant minimalism first-time writer/director Shane Carruth achieves here on a budget of $7,000. The elegance is a partly a side effect of shooting fast and cheap in 16mm and blowing up to 35mm: a deliberate flatness and an industrial brightness that complements the brain teaser of a story. The minimalism spins up from the spareness of the script, from Carruth’s assumption that the audience does not need to be brought up to speed on the concepts he’s exploring. In a suburban garage and with parts scavenged from Wal-Mart and from around the house, engineers Aaron (Carruth) and Abe (David Sullivan) invent a device that hums ominously and appears to futz with the spacetime continuum. So they fiddle around with it, thinking they’ve got all the angles covered — the grandpa paradox and the like. They don’t. This is science fiction for real nerds — and I happily count myself among that group — for those who aren’t afraid of entertainment that ruins the curve by being scarily smart and untroubled by such things as unnecessary exposition. This is a movie that assumes its audience is geeky enough to be comfortable with unexplained techno-talk, to be familiar with the philosophical problems of time travel, and to be hungry enough for intellectual challenge to welcome a story that asks more questions than it answers. So naturalistic and down to earth that it feels totally fresh, and so confounding that it demands multiple viewings, Primer makes my nerdy, geeky little heart very, very happy.