始终是平行四边形

GeoGebra 命令及参数

1. Polygon(A, B, C, D) → poly1, a, b, c, d
2. Angle(poly1) → α, β, γ, δ
3. Rotate(D, α / 3, A) → D'
4. Angle(D, A, D') → ε
5. Rotate(D, (2 * α / 3), A) → D'_1
6. Angle(D, A, D'_1) → ζ
7. Line(A, D') → f
8. Line(A, D'_1) → g
9. Angle(D, A, D') → η
10. Angle(D', A, D'_1) → θ
11. Angle(D'_1, A, B) → ι
12. Rotate(B, γ / 3, C) → B'
13. Angle(B, C, B') → κ
14. Rotate(B', γ / 3, C) → B''
15. Angle(B', C, B'') → λ
16. Rotate(B'', γ / 3, C) → B'''
17. Angle(B'', C, B''') → μ
18. Line(C, B') → h
19. Line(C, B'') → i
20. Rotate(A, β / 3, B) → A'
21. Angle(A, B, A') → ν
22. Rotate(A', β / 3, B) → A''
23. Angle(A', B, A'') → ξ
24. Rotate(A'', β / 3, B) → A'''
25. Angle(A'', B, A''') → ο
26. Line(B, A') → j
27. Line(B, A'') → k
28. Intersect(h, k) → N
29. Intersect(g, j) → I
30. Rotate(C, δ / 3, D) → C'
31. Angle(C, D, C') → ρ
32. Rotate(C', δ / 3, D) → C''
33. Angle(C', D, C'') → σ
34. Rotate(C'', δ / 3, D) → C'''
35. Angle(C'', D, C''') → τ
36. Line(D, C') → l
37. Line(D, C'') → m
38. Intersect(i, l) → G
39. Intersect(f, m) → K
40. Polygon(K, I, N, G) → poly2, k_1, i_1, n, g_1
41. Segment(A, I) → p
42. Segment(A, K) → q
43. Segment(B, I) → r
44. Segment(B, N) → s
45. Segment(C, N) → t
46. Segment(C, G) → e
47. Segment(D, G) → f_1
48. Segment(D, K) → h_1