Two-dimensional design is a feature unique to DRILL that sprang from a desire to give instructors a way to generate custom exams without needing to wade through countless questions by hand. A test is generated by selecting certain skills to be tested, as well as certain objects to which these skills shall be applied. The intersection defines the questions on the exam.
For example, an instructor might want to test the skill of solving 1-variable equations applied to the object of polynomials. Or, to test the skill of factoring applied to both of the objects polynomials and exponential functions. Once the instructor has selected the skills and objects, the server searches through the test bank and announces how many questions fit the desired criteria. The instructor does not need to select them individually -- this is done automatically.
Pictured below are sample choices for the skills and objects. The first checkbox in each list is a "none of the below" choice. Some questions may involve a skill but none of the special objects, or vice versa.