Fast learning with Leitner 3D

Use Leitner 3D to memorize and learn anything in a fast way.
You can study languages, chemistry, history, science, vocabulary, and improve your knowledge. It's very simple!
Also, you can be learning 2 languages together (e.g. English, Spanish) at one time with this application. Here you've flash card with 3 sides.

What is the Leitner?
In this method, flashcards are sorted into groups according to how well the learner knows each one in the Leitner's learning box. The learners try to recall the solution written on a flashcard. If they succeed, they send the card to the next group. If they fail, they send it back to the first group. Each succeeding group has a longer period of time before the learner is required to revisit the cards.
The advantage of this method is that the learner can focus on the most difficult flashcards, which remain in the first few groups. The result is, ideally, a reduction in the amount of study time needed.

Example:
Suppose there are 3 boxes of cards called "Box 1", "Box 2" and "Box 3". The cards in Box 1 are the ones that the learner often makes mistakes with, and Box 3 contains the cards that they know very well. They might choose to study the Box 1 cards once a day, Box 2 every 3 days, and the Box 3 cards every 5 days. If they look at a card in Box 1 and get the correct answer, they "promote" it to Box 2. A correct answer with a card in Box 2 "promotes" that card to Box 3. If they make a mistake with a card in Box 2 or Box 3, it gets "demoted" to the first box, which forces the learner to study that card more often.