I have some. Two beautiful art nouveau books from America 30 years ago, and a bunch of assorted geometrics I picked up in the local charity shop about five years back. I think they are a fantastic idea. Ideal for when I don't have access to my favourite painting by numbers program on the 'puter. I have PTSD. These sorts of occupations are brilliant for putting the brakes on racing thoughts.

They are. I know someone who uses them on public transport in the hopes people will think she's not all thee and ignite her.