Bilston enamel topsy turvy patch box C1790

Unusual cobalt scalloped base enamel patch box.  The lid has a matching border surrounding a white-ground vignette of a pair of topsy turvy couples.  The first way depicts a lady in a black hat with an opposing gent in a green hat.  If you turn the box the other way, the lady is now in a green turban while the man is in a black hat. Bilston C1790.  Original cracked mirror with heavy perishing.