lines on sports fields
... that lines on sports fields were once marked by young children but can now be marked by robots equipped with GPS?
... that <b id="mwASc"><a href="./Line_marker_(sports)" id="mwASg" rel="mw:WikiLink" title="Line marker (sports)">lines on sports fields</a></b> were once marked by young children but can now be marked by robots equipped with <a href="./Global_Positioning_System" id="mwASk" rel="mw:WikiLink" title="Global Positioning System">GPS</a>?