Sometimes those polygons, just, like, overlap man. Here are a handful of ways to symbolize overlapping polygons so you can see what's what and where's where when your polygons start to stack up and get in the way of each other.
Some examples are for when there are only two overlapping polygons and some examples are for when there are boatloads of overlapping polygons.

Check out some other social channels where I share howto's and updates on random map adventures:

http://adventuresinmapping.com
https://www.esri.com/arcgisblog/auth...
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