Big smile! As I mentioned on Facebook today, I just saw a bright yellow cement mixer with the arms of Portugal painted on its side, driving east on 59th Street in Manhattan. Here is the shield:
Here are the full arms:
Thanks to Jorge L. Rivera, III, for supplying this image and the following information:
First documented coat of arms dates from the eleventh century, during the time of Sancho I and Sancho II. That coat showed these same five blue escutcheons charged by silver dots. Ca. 1252, under Alfonso II, the shield was added with the red border and golden castles, as seen here.
From 1385-1816, elements were added until this coat of arms (above) was adopted in 1911. As you can see, it is based on the arms (especially the shield) in use since the eleventh century.