Beautiful Old House Of Global Art Puzzle Mug W Germany

A Beautiful Old ( what I am told ) is a 'Puzzle Mug' in near excellent cond. The mug looks to be a glazed ceramic pottery type material that has a knotted branch look handle that goes around the top of the mug. T are several holes in the mug near the top of the and holes in each knot on the branch around the rim. T also a hole on the inside at the bottom of the handle. The mug is a dark brown and has a beautiful picture of a man and woman on one side. The bottom of the mug on the inside is engraved with a 'Nude' Woman on a blanket and can be seen clearly when held up to a light. The outside bottom of the mug has a label that reads 'House Of Global Art Bavaria W, Germany'. The mug measures approx. 7"H x 4 1/2" in Diameter at the base and weighs nearly 2 lbs. The mug is perfect except for a tiny, tiny fleck in the glaze near the bottom of the handle. I am not sure how old the mug is, but this is a very interesting piece and one that I have never seen before ( see pictures ). Questions or input welcome!