Ooh quick one - I sent Dad some water painting sets. I know some are for kids but it requires very little dexterity to dip a brush and cover the surface, which reveals a pretty picture. There are a lot of sets available to buy and some aren't very suitable for adults but there are some companies which make reusable sets designed for people with dementia. I bought a set called 'classic vehicles' - it just has an outline and you 'colour it in' with water and reveals a classic car, bus, plane etc. I bought a bunch online and sent to the residential home to use for an activity. Dad didn't used to paint, but he's not good with anything fiddly, and he did used to like making things, so it seemed a good idea at the time.