Arthur Cose enhanced the Floem and Vello repositories by delivering robust improvements to text editor reliability, user experience, and rendering accuracy. He focused on refining UI layering, input handling, and cursor management, addressing complex issues such as IME integration and multi-selection logic. Using Rust, Arthur implemented features like overlay window root optimization and caret rendering for ligatures and RTL scripts, while resolving bugs related to event handling and SVG rendering. His work demonstrated a deep understanding of system programming and front-end development, resulting in a more stable, accessible, and responsive editing environment that supports advanced workflows and precise user interactions.