| 摘要 |
<p>A structure in which small pieces of metal are vigorously fluidized in a closed vessel by air circulation is found to be suitable for advertisement and decoration. A portion of the small pieces of metal is intermittently adhered by air flow or magnetic forces to the face of one wall correspondingly to predetermined shapes of letters and/or patterns and the shapes of letters and/or patterns can be intermittently observed for advertisement or decoration purpose.</p> |
