div class=trans-pagebutton class=gotoPage data-page=1Page 1button div class=trans-imagea href=https:reader043fdocumentsusreader043viewer20220225185b0d331f7f8b9a2c3b8cc9abhtml5page1jpg target=_blank img data-url=documentsymbols-are-organized-into-a-hierarchy-of-features-themes-and-categories-symbolshtmlpage=1 data-page=1 class=trans-thumb lazyload alt=Page 1: · The symbols are organized into a hierarchy of features themes and categories Symbols for specific features are the most complex loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mM8Uw8AAh0BTZud3BwAAAAASUVORK5CYII= data-src=https:reader043fdocumentsusreader043viewer20220225185b0d331f7f8b9a2c3b8cc9abhtml5thumbnails1jpg width=140 height=200 adivdiv