jHepWork (jWork) is an environment for scientific computation, data analysis, and data visualization for scientists, engineers, and students. The program is fully multi-platform (written in Java). Programs can be written in the Java, Jython/Python, and BeanShell scripting languages. Matlab/Octave is supported for symbolic calculations. The program can be used to display data and functions in D and 3D. It comes with a friendly IDE and a code assist.
Spaghetti Parenthesis Visualizer is an in-browser (meaning that it doesn't send your code to a server) tool that takes deeply nested conditionals in languages that follow in C's footsteps, including Python, Perl, PHP, and Java, SQL queries, or some Lisp code, and provides two visual presentations that clearly and cleanly display how deep each part of the code is in the layers of nesting.