Back in the 1980s I dismissed this product as just graph paper and never bothered picking up a pad. I seem to recall it was printed with extra lines that could be used to create thick walls in maps. The image of the cover (below) is the only visual trace I can find of the product on the web.
Does anyone have a better photo of the product, or even better a scan/photo of one of the sheets? I've been thinking of printing a similar type of paper and would love to get a better understanding of the dimensions/line weights/colour they used.