These are recent images I converted to vectors with this command:
for i in *.jpg; do convert "$i" "`basename "$i" .jpg`.png" && autotrace -despeckle-level 15 -color-count 6 -input-format PNG -output-file "`basename "$i" .jpg`".svg -output-format svg "`basename "$i" .jpg`.png"; done
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Try it!
Free nature vector art pattern with hand drawn flowers, swirls and ladybugs. Seamless pattern download comes with a light gray background that makes the sketch style graphics standout. Fun setting for kid friendly textiles, nature themed greeting cards, playful websites and personal blogs.
This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:"
http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html