For example, where the identity of the artist intrinsically determines the unique character and value of the art and therefore the requirement can only be met by one artist.
Er enghraifft, pan fo pwy yw'r artist ynddo'i hun yn pennu cymeriad a gwerth unigryw'r gwaith celf, sy'n golygu mai dim ond un artist a all fodloni'r gofyniad.