Spaced Repetition by Wärn is an educational and reference program available on the iPhone platform. This free app allows users to create their own cards to remember various types of information, such as ukulele chords, mathematics, or birthdays. The app follows the spaced repetition technique, where users are presented with a daily test based on their created cards.

The app's main feature is its adaptive learning system. Each card starts at level one, and as users answer correctly, the cards are moved up to higher levels. Cards in higher levels are reviewed less frequently, allowing users to focus on the information they need to practice more. This approach makes it possible to remember anything for the long term.

With its simple and intuitive interface, Spaced Repetition by Wärn provides an accessible way for users to enhance their memory and retain knowledge in various subjects. Whether you're a student, musician, or simply someone who wants to improve their memory, this app offers a valuable tool for effective learning.