Amazing! I love going to Brimfield, but occasions of finding true treasures digging through boxes in far corners happens less and less and less. But then this, and a second early mechanical valentine also listed today--the sorts of lucky finds that keeps me  ever-hopeful. This is quite a rare one, an early mechanical valentine, published by Riedel in Nuremberg, Germany, for English export, 1830s. I have found one reference to this particular valentine, noting is as designed by Heinrich Friedrich Müller, a German book and art seller who a little research shows me also created amazing teleoramas (accordion-style paper peepshows!)

My first photo shows both "before" and "after" views --pull the tab at bottom, and the leaves flip down to reveal the couple concealed within, springing to full life, with a cupid above them, and birds delivering the completion of the message, encircled in ribbons. All hand-colored, in perfect condition, a complete and total wonder and delight! 

3 11/16" x 2 7/8" closed. Excellent antique condition, a rare survivor as such.