This is a lasercut design of a Leitner's learning box for flashcards. (see http://en.wikipedia.org/wiki/Leitner_system)

The DXF file is the design as I used it for A7 cards and 6 mm wood. For different card sizes or wood thickness you need to change the parameters in the OpenSCAD file and render a new DXF file. Other parameters are: the number of trays, the length of the box and the exponential growth factor for the tray size.