Taking a stroll through Harvard Square today, I discovered a modified newspaper distribution box declaring itself "The Stranger Exchange" and inviting whomever to "leave an item" or "take and item" while also promoting a web site, www.thestrangerexchange.com (which was registered in October and redirects to a page within thefuturemachine.com). The white box has handwritten instructions and art on the outside. It's located in Brattle Square across from Hidden Sweets, at the end of a line of newspaper boxes and next to a winter sand bin next to the subway entrance. I opened the door to look inside, and strangers had indeed left a few items. There were five pennies, a broken candy cane and a coupon for $40 off a $120 purchase at some store.[gallery]