Just about the cutest plant ever!  Also known as Peperomia tetragona.

Parallel peperomia are short in stature, but will eventually trail out a bit, making them perfect for a shelf or hanging basket. They do best in moderate to bright but indirect light. In lower light, their stems will become leggy. Let the soil dry out about halfway down the pot before watering. These semi-succulent plants prefer less-frequent, but thorough watering.