"It’s a cloud computing term. When you need a virtual machine in the cloud, or a whole cluster of them, you go on Amazon Web Services or one of its competitors and spin up an ‘instance.’" Alastair used air quotes. "There’s all different sorts—you literally choose the one you want from a menu, and then clone as many as you need. If you are running a computational model of the climate—which is what Eshma does for a living—there’s a particular model, a piece of software, that most in that discipline have standardized on. And it runs best if you set up a cluster, in the cloud, consisting of a particular item on that menu—one sort of instance that the model has been optimized for. So when she got back from that little junket to Pina2bo, she got busy doing exactly that."