To overcome this, a team has combined inkjet printing with an error-correction system guided by machine vision, to allow them to print sophisticated multi-material objects. They used this method to make a bio-inspired robotic hand that combines soft and rigid plastics to make mechanical bones, ligaments, and tendons, as well as a pump based on a mammalian heart. Citizen-scientists help identify an astronomical object that blurs the line between asteroid and comet, and how a Seinfeld episode helped scientists to distinguish the brain regions involved in understanding and appreciating humour. Type 2 diabetes affects hundreds of millions of people around the world and represents a significant burden on healthcare systems. But behaviour change programmes -- also known as lifestyle interventions -- could potentially play a large role in preventing people from developing type 2 diabetes. This week in Nature a new paper assesses how effective this kind of intervention might be.