https://github.com/google/open-location-code/wiki/Evaluation-of-Location-Encoding-Systems https://github.com/google/open-location-code/wiki/Evaluation... One o

https://github.com/google/open-location-code/wiki/Evaluation-of-Location-Encoding-Systems https://github.com/google/open-location-code/wiki/Evaluation... One of the design decisions was to avoid ambiguous characters, so that cuts out at least 9 (I1L 0OB8).