It’s not your typical stop-motion film when characters name pets after Sylvia Plath and read “The Diary of Anne Frank” — or when the story’s inspired by a quote from existentialist thinker Søren Kierkegaard. Movie Review: ‘Memoir of a Snail,’ a stop-motion charmer, examines the shells we build around us And it’s certainly not your typical stop-motion film when you find yourself crying as much as the characters do — in their case, with huge droplets leaking from bulging, egg-shaped eyes so authentic-looking, you expect the screen to get wet. But those are just a few of the unique things about Adam Elliot’s “Memoir of a Snail,” a film that’s as heart-tugging as it is technically impressive, a work of both emotional resonance and great physical detail using only clay, wire, paper and paint. One thing Elliot’s film is not, though, is for kids. So please take note before heading to the multiplex with family in tow: this film earns its R rating, as you’ll discover as soon as young Grace, voiced by Sarah Snook, …