The article presents a visual framework to show how sharing knowledge between companies can help them learn and innovate. By using a four-quadrant picture, the researchers explain how firms can benefit from spillover effects in a local innovation system. They suggest different ways that knowledge can be exchanged among companies, each affecting how well they can use new technologies. The researchers find that some ways of sharing knowledge are more efficient than others. They also expand on these basic models to explore more possibilities for learning and innovation.