| 摘要 |
<p>The invention provides a rotatable sign comprising a support frame and first and second display elements each pivotally mounted within the frame so as to be freely rotatable within the frame about a common longitudinal axis or adjacent longitudinal axes, each display element comprising a substantially planar central portion and two opposed side edge portions one of the side edge portions being inclined at an obtuse or at least right angle to one face of the central portion and the other side edge portion being inclined at an about equal obtuse or right angle to the other face of the central portion whereby the side edge portions of each display element are arranged to enable wind to cause the display elements to contra-rotate with respect to each other.</p> |
