Xfinity XB3 horizontal stand

This foot holds the Xfinity XB3 modem (Arris TG1682) horizontally level when sitting on a shelf. Attach with bluetack or hot glue.

I'm using bridge mode with [WiFi disabled](https://gist.github.com/pmarks-net/af40dba69272806c1ec9cbe71429d2e7), so the antenna orientation doesn't matter.