Colloids are very small particles that you cannot see with the naked eye. They are only a millionth of a metre in size. Despite their size, they have very spectacular properties. If you put them together, they will spontaneously form new structures and thus new materials. We are already using this self-assembly to build new advanced materials, such as more efficient solar cells. If we use colloids that are irregular in shape or form specific bonds, the structures become even more extraordinary. But there is a catch. In those cases, self-assembly goes wrong more often. The result: errors creep into the structure of our new material, causing it not to have the desired properties. Why do these errors creep in? That is exactly what we want to find out with our research. Using a powerful microscope, we watch colloids in action and follow the self-assembly process from start to finish. In this way, we are trying to understand when and how particles come together and -- more importantly — when it goes wrong, so that we can control errors in the future. This is how I hope to realise my dream: to create new materials that build themselves entirely.