| 摘要 |
A board intended to be used as a writing surface is provided with a frame and with a complementary border constituting one inseparable entity. The frame is continuous all around the periphery with a cross-section comprising three flanges. One flange is external to the other two, a second flange is equipped with a rim positioned behind the board and bearing against a foot formed on the complementary border, and the third flange bears against the front face of the board.
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