Carbon nanotubes (CNTs) are microscopic tubular structures that engineers ‘grow’ through a process conducted in a high-temperature furnace. The forces that create the CNT structures known as ‘forests’ often are unpredictable and are mostly left to chance. Now, a researcher has developed a way to predict how these complicated structures are formed. By understanding how CNT arrays are created, engineers can better incorporate the highly adaptable material into devices and products.