This is MetaPost, version 1.999 (TeX Live 2015/Debian) (kpathsea version 6.2.1)  30 OCT 2018 14:17
**vwline.mp
(/usr/share/texlive/texmf-dist/metapost/base/mpost.mp
(/usr/share/texlive/texmf-dist/metapost/base/plain.mp
Preloading the plain mem file, version 1.005) ) (./vwline.mp [1] )
1 output file written: vwline.svg