egg:

take a short line, of fixed weight which it has to be in xara, made with the line tool - then imagine just a quick drag on the end with the mouse/pen to bring it immediately to needle point - hey presto, an eyelash

imagine what you could do with such a tool when say, changing the expression on someone's face in a cartoon, or any such drawing situation, quickly, easily, expressively; no need to redraw it, no need to make a new brush, just change it

no need to use a brush at all