Don

Here is a variant - I have this one that I got in a local gar(b)age sail.  

Ed

https://www.jimbodetools.com/products/rare-mc-clellan-february-18-1890
-patent-corner-brace-72944">https://www.jimbodetools.com/products/rare-mc-
clellan-february-18-1890-patent-corner-brace-72944