<P> Although patented by Guinness, the widget was actually invented by John Lunn, MD of Mclennons of Birmingham, who went on to invent a second for Whitbread and Heineken, so that Whitbread could launch Draught Boddingtons in a can and Murphy's . Lunn then later invented a third widget, the floating one, with two one - way valves, which is the widget that all brewers use now . </P> <P> The term widget glass can be used to refer to a laser - etched pattern at the bottom of a beer glass which aids the release of carbon dioxide bubbles . The pattern of the etching can be anything from a simple circular or chequered design to a logo or text . </P> <P> The widget in the base of a beer glass works by creating a nucleation point, allowing the CO to be released from the liquid which comes into contact with it, thus assisting in maintaining head on the beer . This has become increasingly popular with Fosters, Estrella and others using them in public houses in the UK . </P>

How does a widget work in a pint glass
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