Introduced by the Ideal Toy Co. in 1969, Flatsy dolls bridged the gap between two-dimensional paper dolls and their high-fashion 3-D cousin Barbie. With their long, "real" hair and brightly colored, changeable clothes, Flatsys had different themes, each with clothes and accessories to match. Since the 1970s, the dolls have become sought-after collectibles, though serious collectors warn of prevalent knockoffs. How do you know if your Flatsy is real? Look at the shoes. They must be plastic, not painted. Real Flatsys also bear a "©1969 Pat. Pend. Hong Kong" copyright stamp on the back, while fakes will often say just "Hong Kong."