A boxable drywall corner trim that can include an elongated semi-rigid member that forms a pair of flanges joined at a grooved hinge along a centerline. Each of the flanges can have a thinner part and a thicker part joined at a step that is approximately parallel to the centerline a predetermined distance...http://www.google.es/patents/US7673428?utm_source=gb-gplus-sharePatente US7673428 - Boxable mesh adhesive drywall corner trim
