AlgoSim

AlgoSim is a very intuitive and advanced mathematical software for numerical analysis and visualisation, and physical simulation.

It offers a unique design and an almost poetic depth of features.
AlgoSim is a command-line program, so you should only expect to be able to edit the last line of the console.
Every computation in AlgoSim runs in its own thread. To terminate the current computation, simply execute the command "quit" (with no argument; try pressing Esc to insert this command in the prompt).