Invention: One thin light wooden black multi-folders box can be transformed to a presentation architectural materials flat board.
<a href="//commons.wikimedia.org/w/index.php?title=User:Vincshekhan&amp;action=edit&amp;redlink=1" class="new" title="User:Vincshekhan (page does not exist)">Vincshekhan</a>
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<span class="int-own-work" lang="en">Own work</span>