What are some of the key innovations that a marker has undergone since its original invention?

Since its original invention, markers have undergone several key innovations, including the development of non-toxic, water-based inks for safer use and improved environmental impact. Advances in tip design have led to various styles, such as fine, chiseled, and brush tips, enhancing versatility for artists and writers. Additionally, the introduction of erasable and permanent markers has expanded their applications across different fields. Finally, innovations in marker casing materials have made them more durable and user-friendly.