The 30-90 nap rule is a productivity system developed by entrepreneur and author, James Clear. The system is based on the idea that taking regular breaks from work can help improve focus, increase creativity, and reduce burnout. The system works by dividing work into 30-minute increments, followed by a 90-minute nap. During the 30 minutes, the user should focus on a single task and avoid distractions. After the 30 minutes, the user should take a 90-minute nap to relax and recharge. The nap should be taken without the use of technology or other distractions. After the nap, the user can then return to their work with a refreshed perspective. The system is designed to be repeated throughout the day, allowing the user to work in short bursts of productivity and recharge as needed.