I am forever looking at, and for, old sets of blocks of interesting design, but I have never ever seen another of this particular set, produced by The Embossing Co. of Albany, NY, which also produced the much better known and widely distributed Color Cubes. I have found one reference out there to another set similar to these with the same basic box, but for "Curve Design" rather than "Angle Design" blocks, and dated to the mid 1930s. A writer about those noted they would have been a very effective educational toy for teaching the mechanics of working with typographical printers' ornaments, which I think could be said for these too (Letterology.com)--but, like Color Cubes, certainly the intent was to facilitate design thinking and pattern play much more broadly. I am guessing there were not too many of this set produced (perhaps the patent was never granted...) but I love how modern feeling they are (with a late 70s-early 80s feel to my eye), and also, with the reverse side of the blocks painted black, how much they facilitate the creation of patterns that look rather like stained glass windows!
Box measures 11" x 11 x 1/2”. Some paint loss on some blocks (especially the red) as evident, but overall good condition. Wear to the sides and tears to the corner of the box. Front of box shows lots of pattern design possibilities!