...The user builds his system model by selecting predefined blocks from a block library and simply wiring the blocks together. Each block of the diagram performs a function. Users can also create custom blocks in Java and add them to the JMCAD block library.
JMCAD is a block diagram language for creating complex nonlinear dynamic systems.
jQuantum is a Java program to simulate a quantum computer, to design quantum circuits, and to visualize the execution of quantum algorithms. Another main purpose, however, is to create images in your head, and thereby - understanding.