Seven is a character. I tend to feature Mac more in this project because he's usually an easier subject (he's more like a dog), but Seven can be very funny with his oversized ears, vampire fangs and quirky attitude. Specs of dust very much stand out against his soft black fur... he is the dust collector.
@carla42 his name derives from SR-71, a neat looking plane also known as the Black Bird. Ever since kitten-hood, this guy often jetted out at great speed making growling sounds as he ran - but SR-71 is a long name, so we shortened it to Seven. I've also always said he's my lucky black cat ("lucky number seven")... It just fit. :)