Buick - basic info and current lineup
Buick's founder was David Dunbar Buick in 1903, when it was an independant motor company - nowadays, it's a division of GM. In fact, it was the huge Buick's success that made the creation of GM poossible.
Buick's Trishield (a company logo) represents three car models produced. At the time when Trishield was adopted (1959-1960), those were LaSabre, Invicta and Electra - currently, The Buick Motor Division produces three models, too (Lucerne, LaCrosse and Enclave).
Over the years, a front grille remained the main design point of all Buicks. Back in 1950's, at the bumper/curves/colors peak, Buick's front grille were crossed over the bumper, exposing what resembled teeth. That's why the Buick's front grille was called a "Dollar Grin".
Although they were put aside from time to time, highly polished grille ribs were, and still are, Buick's identity card .. at least when it comes to styling.
Since company policy was not to have too many models (only three at most times), they can focus on each of models to the maximum. Buicks were always fine cars ... and they still are.
Current Buick Lineup:

-
Lucerne - full-size sedan
-
LaCrosse - mid-size sedan
-
Enclave - luxury crossover