This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
CalkinWilf spiral.svg Calkin Wilf tree The sequence is depicted as the red spiral tracing through the tree own David Eppstein Files by User David Eppstein from en Calkin Wilf tree and sequence Breadthfirst search
Page 2023 Free-images.com. All images are Public Domain