Bay seniors who don’t believe that the next big thing in skin art is animated tattoos are encouraged to check out the Body Art Expo at the Cow Palace September 5 to 7. This is billed as the world’s largest of such affairs with 300 artists demonstrating their piercing and tattooing skills. $20. You already know, of course, that 40% of people under 20 in the US have tattoos. They probably won’t welcome any of our comments about what happens to these designs when they get to be our age.