American (ANSI) symbol for a <a href="https://en.wikipedia.org/wiki/NOR_gate" class="extiw" title="w:NOR gate">NOR gate</a>
<a href="https://en.wikipedia.org/wiki/nl:User:El_barto" class="extiw" title="w:nl:User:El barto">El barto</a> at <a href="https://en.wikipedia.org/wiki/nl:" class="extiw" title="w:nl:">Dutch Wikipedia</a>
CC BY-SA 3.0
Originally from <a class="external text" href="https://nl.wikipedia.org">nl.wikipedia</a>; description page is/was <a class="external text" href="https://nl.wikipedia.org/w/index.php?title=Image%3ANOR_poort.jpg">here</a>.