What are sense-objects made from?

The common sense-objects are light, sound, smells, tastes, touch, and ideas. The origin must be form. What is form? > The four great elements and the form derived from the four great > elements: this is called form. Thus we assume the sense-objects are derivatives of the four great elements, but what is more? Given the often anomalous classification of intellect as mind or consciousness, I even wonder if its counterpart, idea, is form at all. Is there further elucidation on the matter, like that of the Sankhya school?