The Waco location was also known as Harry Lewis Triple XXX. It appears this was remodeled as Bill Wood's Famous Foods. There was another Triple XXX Root Beer in Seattle, WA.

The Issaquah location is one of two Triple XXXs that remain. In the 1960s, it was moved to this spot, bringing the giant sign with it by crane. Although early Triple XXXs were built around a giant root beer barrel, I'm not sure if the one in Issaquah ever had a 3-D barrel. This drive-in hosts classic car shows on weekends during the summer. For more, see their website.

The other survivor is the Triple XXX Family Restaurant - a popular hangout near Purdue University. They still sell the original Triple XXX root beer. The stand opened in 1929 and was the first drive-in in Indiana. The place eventually became a single story restaurant. In 1987, they added a second story. The restaurant now seats 49 and uses the motto "On the Hill but on the Level". They are known for their 100% chopped sirloin sandwiches (burgers), ground in the kitchen and floured just like they have been since 1929. For more, see their website.

I'm not sure if this patented design from 1952 played a role in Triple XXX building design. For more barrel-shaped buildings, see this page.