Canvas is different from other fabrics because it has no front or back. This is the result of a particular weaving method that alternately crosses the odd and even warp threads, to let the weft thread through.
Virgin wool
This is what we call fibres that come from the first shearing of a sheep or lamb. They have been neither spun nor felted nor part of any other finished product, and contain no more than 0.3% of impurities.