Do you remember how your teachers teached you about letters? They would made some flash cards and stuck them on the board. (1) They would show each letter and dictate it to let us had an impression for those letters; (2) then they would dictate one letter and ask us which card is related to; once we knew the letters more, (3) they would try to ask us to dictate each letter on the card. By the way, (4) they would try to make us familiar with those letters by homeworks, examings, etc.
Well, on the stance of a learner, the first three points are the three modes of this APP's game mode and the role of your device is the instructor; then, it will remind you to review your study based on Ebbinghaus Forgetting curve in order to make your memory to be a long-term one.
On the stance of a instructor, what are the cards? As long as you put some text or image files into a single folder, those files will be flash cards in this APP and their file names will be their answers by default.
Do you want to test this APP before you install it? Sure, you can try its web version on this App's main web page. Besides, you also can download those containers you like through this APP.
You'll find that some cards in some categories even can fix their position, size, etc. Yes, most of that settings can be done in the play page of this APP. Once you upload its folder to the web site, it would be a new demo for everyone to play on the web.