Business Matters - Why are adult colouring books so popular? - ÃÛÑ¿´«Ã½ Sounds

Business Matters - Why are adult colouring books so popular? - ÃÛÑ¿´«Ã½ Sounds
Why are adult colouring books so popular?
A craze for adult colouring books has caused a global shortage in coloured pencils.