It's very tricky with pictures. Everyone here will say the same: 'I need it in my hands, otherwise I'm blind!'
However...decanters are mostly made with lead in the mixture! It makes the glass clearer, reduces the risk of marks and bubbles, and is prerequisite for any serious cutting or deep engraving. (also takes on a good 'shine' after polishing)
Assuming that the decanter may well be older than 70 years, you have to think of 'design' in the same way you would furniture!
Chippendale never made a chair in his life, he just designed them, and his book was used by thousands of small workshops around the country to produce 'Chippendale' furniture. Similarly, glass workers had (have) a library of techniques and styles and often a pile of pattern books to use as reference. Glass factories often provided 'blanks' to the trade.
This means that an unkown quantity were produced from an unlimited number of design/combinations, and very very little of it is identifiable, or marked.
Square decanters are sometimes part of a 'Tantalus' set (three or four decanters in a lockable 'case').