From my Dad's collection which I'm now in charge of since he has relocated near my Brother in Corbin, KY at a skilled nursing facility. He'll be 90 in October. Her we have two interesting pieces with odd multiple markings. The white one has the L/M triangle with the cat. number 680 but also has a stylized FP possibly for Findlay Porcelain. The brown one clearly has both the PP INC. and L/M markings.