Yeah . found another one :
This thing looks totally weird ! It's a plastic ( not styrene thing ) . It's made for doing angular things .Yup Put your styrene or Clear ( showcase tops ) in there and glue them together . Now besides this shape on the thing there are two more . A larger inverted pyramid and an inverted hexagon .
I have no idea what you'd use them for , But I believe this could be a useful tool for the scratch builder . It's made by Morton Glass Works in Morton Illinios . Now , I do know it is in the Delphi Stained Glass Catalogue . Website number is 7155 . It's called a Morton Assembly Tray .
I recommend using any tool that works . Stained Glass Hobby Sites and Catalogues have many , We as modelers can use . T.B.