Potentially unfree, potentially PD-Simple version, as noted by [1]. Considering, however that it is only squares, I think it qualifies for PD-Simple, and I myself vectorized it, releasing it under CC0 if possible. Admins, please review the legitimacy of both files' copyright statuses.
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I, the copyright holder of this work, hereby publish it under the following license:
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse
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