The top left corner of the photo below shows an orb I photographed next to a high window in Grand Central Terminal in New York on October 21, 2016. The other seven photos show orbs I previously photographed over the past few months, as reported here and here. Notice that all 8 photos have the same stripe pattern. The strange stripe looks rather like an aerial view of a winding road ending in a cul-de-sac, so I'm going to start calling this the "cul-de-sac" motif. It is one of quite a few recurring motifs that are appearing in the mysterious orbs I photograph, as shown here (another being the "inverted Y" motif I have photographed 5 times, as shown here).
The photos taken here were only 8 of thousands of photos I took during a period of a few months, and the symbol above appeared only in these photos scattered among those thousands. After each photo was taken, there were dozens of other photos that showed no such symbol.
In six of the photos, the stripe begins or ends on the edge of the orb. In the third photo, the stripe begins on the edge of the orb, and ends on the edge of a flag.