egister user-defined icon set -->
    <polymer-ui-iconset id="my-icons" src2="packages/polymer_ui_elements/polymer_ui_iconset/my_icons.png" width="96" iconsize="24"
        icons="location place starta stopb bus car train walk">
    </polymer-ui-iconset>

    <!-- use prefix (e.g. my-icons:location) to use user-defined icon set -->
    <polymer-ui-toolbar>
      <polymer-ui-icon-button icon="my-icons:location"></polymer-ui-icon-button>
      <div flex>user-defined icon set</div>
      <polymer-ui-icon-butto