| 摘要 |
Disclosed is a normal triple prism synthetic ball of 30 degree angles. The sphere is composed of 30 identical parts by a plug graft. A rectangular piece of paper with a length and width at the ratio of 1:0.4409 is taken, and in accordance with the left corner bisector positive broken line and the right corner bisector positive broken line, is folded into a parallelogram, and again, in accordance with the upper link positive broken line and the lower link positive broken line, is folded into a coincident rectangle, and is then folded into parts. A plug graft of the normal triple prism is completed. Five normal triple prisms are one group, i.e. a five angle group. A pure sphere with 20 normal triple prisms is prepared by plug grafts, i.e. the normal triple prism synthetic ball of 30 degree angles. The preparation of the normal triple prism synthetic ball of 30 degree angles is simple and easy; the synthetic step is both regular and smooth; and the molding is both beautiful and sturdy. |
