Turtle System X
The Turtle System X is a cross-platform version of the Oxford Turtle System, an educational IDE with built-in support for Turtle graphics, designed to help students learn to program. The system supports programming in BASIC, Pascal, and Python. It includes compilers for these languages (with hundreds of precise and easy to understand error messages), compiling to a pseudo-code (or 'pcode') for a stack-based virtual machine. The compiled pcode and the contents of the virtual machine's memory can be inspected by advanced students wishing to learn some of the fundamentals of computer science.