可修改固体：垂直于y轴的截面为正七边形

GeoGebra 命令及参数

1. Segment(H, I) → s_1
2. Midpoint(s_1) → A_1
3. Line(H_1, H_1 - (1, 0, 0)) → l_1
4. Rotate(I, (2 * pi / 7), H_1, l_1) → I'
5. Rotate(I', (2 * pi / 7), H_1, l_1) → I''
6. Rotate(I'', (2 * pi / 7), H_1, l_1) → I'''
7. Rotate(I''', (2 * pi / 7), H_1, l_1) → I_1
8. Rotate(I_1, (2 * pi / 7), H_1, l_1) → L_1
9. Segment(J, K) → q_1
10. Midpoint(q_1) → Z
11. Line(D_1, D_1 + (1, 0, 0)) → g
12. Rotate(J, (2 * pi / 7), D_1, g) → J'
13. Rotate(J', (2 * pi / 7), D_1, g) → J''
14. Rotate(J'', (2 * pi / 7), D_1, g) → J'''
15. Rotate(J''', (2 * pi / 7), D_1, g) → E_1
16. Rotate(E_1, (2 * pi / 7), D_1, g) → K_1
17. Intersect(lower, h, (-10, -10.839071529076453)) → C
18. Intersect(upper, h, (-10, 0)) → B
19. Segment(C, B) → q
20. Intersect(upper, q, (-10, 0)) → G
21. Midpoint(C, G) → T
22. Line(T, T + (1, 0, 0)) → m
23. Line(F_1, F_1 + (1, 0, 0)) → n
24. Rotate(G, (2 * pi / 7), F_1, n) → G'
25. Rotate(G', (2 * pi / 7), F_1, n) → G''
26. Rotate(G'', (2 * pi / 7), F_1, n) → G'''
27. Rotate(G''', (2 * pi / 7), F_1, n) → G_1
28. Rotate(G_1, (2 * pi / 7), F_1, n) → J_1
29. Midpoint(s_1) → E
30. Midpoint(q_1) → F
31. Line(B, D) → i
32. Sphere(B, d) → e
33. Segment(C, B) → p
34. Textfield(upper) → InputBox1
35. Textfield(lower) → InputBox2
36. Textfield(a) → InputBox3
37. Textfield(b) → InputBox4
38. Segment(C, G) → k_1
39. Line(C, G) → j
40. Polygon(C, G, G', G'', G''', G_1, J_1) → poly1, m_1, r_1, a_1, b_1, c_1, d_1, f_2
41. Sphere(G, T) → k
42. Segment(G', G'') → l
43. Segment(G'', G''') → r
44. Segment(G''', G_1) → s
45. Segment(G', G) → i_1
46. Line(Z, Z + (1, 0, 0)) → f
47. Segment(J, J') → f_1
48. Polygon(H, I, I', I'', I''', I_1, L_1) → poly2, h_2, i_2, s_2, t_2, a_2, b_2, c_2
49. Polygon(K, J, J', J'', J''', E_1, K_1) → poly3, g_1, j_1, n_1, p_1, e_1, j_2, k_2
50. Segment(G_1, J_1) → g_2
51. Segment(J_1, C) → l_2
52. Segment(J', J'') → m_2
53. Segment(J'', J''') → n_2
54. Segment(J''', E_1) → p_2
55. Segment(E_1, K_1) → q_2
56. Segment(K_1, K) → r_2
57. Segment(I', I) → d_2
58. Segment(I', I'') → e_2
59. Segment(I'', I''') → f_3
60. Segment(I''', I_1) → g_3
61. Segment(I_1, L_1) → h_3
62. Segment(L_1, H) → i_3
63. CurveCartesian(t, lower(t) - (cos((2 * pi / 7)) * (upper(t) - lower(t))), (sin((2 * pi / 7)) * (upper(t) - lower(t))), t, a, b) → o_2
64. CurveCartesian(t, upper(t) + (cos((2 * pi / 7)) * (upper(t) - lower(t))), (sin((2 * pi / 7)) * (upper(t) - lower(t))), t, a, b) → c
65. CurveCartesian(t, (0.5 * (upper(t) + lower(t))), ((0.5 * tan((5 * pi / 14))) * (upper(t) - lower(t))) + (0.5 * (upper(t) - lower(t)) / cos((5 * pi / 14))), t, a, b) → v
66. CurveCartesian(t, ((-(upper(t) - lower(t))) * sin((5 * pi / 14))) + (0.5 * (upper(t) + lower(t))), ((0.5 * (upper(t) - lower(t))) * tan((5 * pi / 14))) + (0.5 * (upper(t) - lower(t)) / cos((5 * pi / 14))) - ((upper(t) - lower(t)) * cos((5 * pi / 14))), t, a, b) → t
67. CurveCartesian(t, ((upper(t) - lower(t)) * sin((5 * pi / 14))) + (0.5 * (upper(t) + lower(t))), ((0.5 * (upper(t) - lower(t))) * tan((5 * pi / 14))) + (0.5 * (upper(t) - lower(t)) / cos((5 * pi / 14))) - ((upper(t) - lower(t)) * cos((5 * pi / 14))), t, a, b) → w
68. Surface(u, lower(u) - ((v * cos((2 * pi / 7))) * (upper(u) - lower(u))), ((v * sin((2 * pi / 7))) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → o
69. Surface(u, upper(u) + (v * (cos((2 * pi / 7)) * (upper(u) - lower(u)))), ((v * sin((2 * pi / 7))) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → u
70. Surface(u, lower(u) - ((upper(u) - lower(u)) * cos((2 * pi / 7))) + ((v * (upper(u) - lower(u))) * sin(pi / 14)), ((upper(u) - lower(u)) * sin((2 * pi / 7))) + ((v * (upper(u) - lower(u))) * cos(pi / 14)), u, a, b, v, 0, 1) → o_1
71. Surface(u, upper(u) + ((upper(u) - lower(u)) * cos((2 * pi / 7))) - ((v * (upper(u) - lower(u))) * sin(pi / 14)), ((upper(u) - lower(u)) * sin((2 * pi / 7))) + ((v * (upper(u) - lower(u))) * cos(pi / 14)), u, a, b, v, 0, 1) → u_1
72. Surface(u, lower(u) - ((upper(u) - lower(u)) * (cos((2 * pi / 7)) - sin(pi / 14))) + (v * ((0.5 * (upper(u) + lower(u))) - (lower(u) - ((upper(u) - lower(u)) * (cos((2 * pi / 7)) - sin(pi / 14)))))), ((upper(u) - lower(u)) * (sin((2 * pi / 7)) + cos(pi / 14))) + ((v * (upper(u) - lower(u))) * cos((5 * pi / 14))), u, a, b, v, 0, 1) → u_2
73. Surface(u, (0.5 * (upper(u) + lower(u))) + ((v * (upper(u) - lower(u))) * sin((5 * pi / 14))), ((0.5 * (upper(u) - lower(u))) * tan((5 * pi / 14))) + ((upper(u) - lower(u)) * sin((5 * pi / 14)) / tan((2 * pi / 7))) + (((1 - v) * (upper(u) - lower(u))) * cos((5 * pi / 14))), u, a, b, v, 0, 1) → v_2