This paper describes interactive applications used to illustrate an advanced course on multivariable control. The direct manipulation of features in graphics, such as eigenvectors in the phase plane or observer eigenvalues in the complex plane, gives the student the means to explore not only the effect of parameters in the ranges usually considered as realistic, but also to observe the consequences of more extreme choices and get a better understanding of the design methods. The applications are implemented in Sysquake to provide a simple user interface, consistent across a wide range of examples from classical to advanced control.