Questions API's custom question type alows you to create your own questions, giving you full control over the rendering of the response area, the user interaction with the question, and the scoring of the response.
Here you can find some custom question examples.
Demonstrates a simple and easy implementation of a custom question.
Demonstrates how to implement a Math Custom question using Learnosity Mathcore.
Demostrates a custom implementation of the Short Text question type where you can rewrite the question JSON to define your own custom questions.