An SSH server with a simple to use API to become a customized interface.
Spacecmd is a Python application that speaks SSH, enabling you to create a service as a UI built on SSH. With your own custom logic, you can make a terminal application run hosted remotely by you.
For a small demo of an application which simply displays a matrix, use the follow:
ssh -p 2200 matrix.pereira.io
A goal for this is to make a sandboxed shell environment so you can create complex shell puzzles and interfaces with ease in Python.