There’s a point every fall when backyard evenings start getting cut short. The sun drops, someone grabs a hoodie, and before long everyone has drifted back inside. Wood fire pits leave your clothes smelling like smoke, and patio heaters keep you warm without giving anyone much of a reason to gather around them. Ninja thinks it can do both with the Ninja Fireside360, a propane fire pit with a built-in outdoor heater. We spent the past few weeks finding out whether it can keep a group outside long after dark.