*group messages icon* is derivative work

    based on https://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Group_half_security.svg/120px-Group_half_security.svg.png from https://commons.wikimedia.org/wiki/File:Group_half_security.svg

    formerly was icon from PICOL, PIctorial COmmunication Language, http://picol.org

    licensed under Creative Commons Attribution 3.0 Unported license
