This exercise creates random intervals and you should try to identify them.
If you are using the buttons interface, then you can right-click on
the buttons to hear the interval they represent.
On the config page of the exercise, there is a combo box where you can
select different ways to answer the question. Currently there is a piano,
guitar, bass and a few types of accordion in addition to the default
buttons interface. Below is a screenshot showing the piano interface.