: The design features 13 arrows, 13 olive leaves, and 13 letters in the motto E Pluribus Unum . Official explanations from the National Archives and Wikipedia note these represent the "solid compact" of the several states.
The phrase "13. Us" likely refers to the or colonies that formed the United States. A "solid paper" looking at this topic often refers to historical and political analyses of the Great Seal of the United States or foundational documents like the Declaration of Independence . Foundational "13" Symbolism in the US 13. Us
: A famous 2015 study attempted to replicate 100 psychology experiments, finding that only about one-third produced significant results, often with effect sizes half as strong as the originals. : The design features 13 arrows, 13 olive