This crafting medium consisting of very small particles of metal which is held in a modelling clay which burns way in the kiln leaving the valuable metal. What is it called?

These show excellent chemical, thermal, and oxidative stability and are practically insoluble in all common solvents. They conduct electricity - which is not their normal property!

Heated in hot water - at 62 degrees centigrade, the granules form a mass of ‘clear’ material that can be shaped into almost any form

Polytetrafluoroethylene, employed as a coating in paints, fabrics, carpets and clothing (school uniform trousers) to repel liquids.

Printed images with an illusion of depth, or the ability to change or move as the image is viewed from different angles.