Today's lesson is: What goes around, comes around. And sometimes it comes with two heads. Robert Shapiro, owner of an East Village T-shirt shop, can attest to this. When not devising morally upright T-shirts - "No child is born a racist," "There's more to life than looking like a Gap ad," etc. - he spends his spare time rescuing unwanted reptiles. And this summer, one of them - a constrictor - gave birth to a bouncing baby boa. With two heads. It is the only known two-headed boa in the world, worth hundreds of thousands of dollars. "It's like a...