By definition, logos are meant to be unique definers of a company or organization, but it turns out, some logo shapes are trendier than others, according to this graph by logo design blog Emblemetric

The y-axis represents "a ratio of the share of shape type in new logos in a given year to the share of shape type in dying logos from that year," meaning if 20 percent of circle logos die this year and 20 percent of new logos are circles, then the ratio is 1. Emblemetric analyzed data from the U.S. Patent and Trademark Office to make the graph. 

As you can see, circle (Target), triangle (The New York Knicks), and square logos (Facebook) are in right now. And people apparently really did not want polygon-shaped logos to define them in the mid-90s. 

Emblemetric predicts that in the future, that black line for square logos will continue to rise: "Their compatibility with new visual forms of identity such as favicons and social media profile photos may push them to greater heights."