| 摘要 |
An opaque box (12) has a lens (14) in its upper face (13). The opaque rear face (15) has openings covered by transparent, light-dispersing material. These are progressively illuminated as the sun's rays are focussed on them. Alternatively, a plain mirror (16) is mounted obliquely against the rear face to project the light point against openings (17) in the front face. The box could be made of coated transparent material, with apertures to mark the sun's passage. The apertures could be lines or symbols to represent hours and their fractions.
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