I don't know, but look to wiki - modification of metapost - and there are links to books about metapost with plenty of samples. Some of them is quite easy to modify and use for user symbols. m. Jan 5, 2014 v 8:43 PM, Dirk Peinelt <dirk.peinelt@t-online.de>:

have anyone developed a dynamic „dip strike symbol“ for stratification at this time?

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