It’s a surface with only one side and one boundary.
An infinity symbol is the möbius strip's representation.
The Möbius strip was created by the German mathematician and astronomer August Ferdinand Möbius in 1858.
In mathematics, a Möbius band, strip, or loop, is a surface with only one side and only one boundary curve. The Möbius strip is the simplest non-orientable surface.
For more than 160 years the Möbius strip has been an object that defies the laws of physics.
You can make a Möbius strip with a piece of paper and tape.
If its full length were crawled by an ant, the ant would return to its starting point having walked “both” sides of the paper without ever crossing an edge.
But I believe that an ant will stop somewhere in between without making it to the full length.
In a normal loop, an ant could only crawl along the top or the bottom.
The simplest example is the Mobius band is a twisted strip with one side and one edge.