| 摘要 |
<p>The mask is used for checking the results of a number game and comprises a flat plate of transparent plastic. This has a number of parallel slots or rows of perforations corresponding to the squares on the game. The positions of the combination of winning squares is marked on the plate by placing opaque buttons in the slots or perforations. The finished plate is then placed over the results card, a winning combination showing no crosses or maked squares. A flat magnifying lens can also be used to improve reading.</p> |
