Two vertical, three horizontal lines (1965-1966) by George Rickey inside the Sculpture Garden at Kröller-Müller Museum/The Netherlands
<a href="//commons.wikimedia.org/wiki/User:Staka" title="User:Staka">Staka</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>