| 摘要 |
PROBLEM TO BE SOLVED: To provide colored sands for a sandbox formed by coloring the sands with coloring materials varying with each of the sizes of particles. SOLUTION: The sands formed by pulverizing the natural sands and seashells are sorted to the sizes varying in the sizes of the particles and are colored with the coloring materials varying with each of the sizes of the particles. Even the sands of the different colors are mixed, such sands can be sorted to the sands by each of coloring with sieves varying in the sizes of meshes.
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