While browsing the internet, I discovered this Omega vintage Chronograph that I'd never seen before.
Not only does it have beautiful angular lugs, but it's also powered by the caliber 321 or its ancestor.
Here are four examples.
EXAMPLE NO. 1
34 mm pink gold case. Manufactured in 1947-1948



The watch is presented as "equipped with the
27 caliber,
ancestor of the
321"

credit: Jean-Marc Botazzi
EXAMPLE NO. 2
35 x 45 mm yellow gold case from 1947