X is a thread of filament from which Y is made. If prepared from plants and animals, it is known as Z fibres whereas by humans it is known as W fibres. Synthetic fibres are nylon, rayon, polyester, acrylic etc.
What is Y?
Fibre is the basic unit of raw material having suitable length, pliability, and strength for conversion into yarns and fabrics/material/cloth.
A fibre of extreme length is a filament. Fibres can occur naturally or can be produced artificially.
Here, X is a fibre, Y is the cloth/fabric/material. Z is the natural fibre and W is the artificial or human-made fibre.
paper/book is an example of products of natural polymer (cellulose), pen is an example of industrial product of synthetic polymer.