可调节立体：平行y轴的等边三角形横截面

GeoGebra 命令及参数

1. Segment(H, I) → s_1
2. Midpoint(s_1) → E
3. Segment(J, K) → q_1
4. Midpoint(q_1) → F
5. Intersect(upper, h, (0, 10)) → B
6. Intersect(lower, h, (0, -6)) → C
7. Segment(C, B) → q
8. Intersect(upper, q, (0, 10)) → G
9. Midpoint(C, G) → T
10. Line(B, D) → i
11. Sphere(B, d) → e
12. Segment(C, B) → p
13. Polygon(C, G, U) → q1, f_1, g_1, n_1
14. Polygon(K, J, W) → q2, l, m, n
15. Polygon(Q, P, V) → q3, r, s, t
16. Textfield(upper) → InputBox1
17. Textfield(lower) → InputBox2
18. Textfield(a) → InputBox3
19. Textfield(b) → InputBox4
20. Segment(K, W) → f
21. Segment(W, J) → g
22. Segment(Q, V) → j
23. Segment(V, P) → k
24. CurveCartesian(t, (0.5 * (upper(t) + lower(t))), ((sqrt(3) * 1 / 2) * (upper(t) - lower(t))), t, a, b) → c
25. Surface(u, ((1 - v) * lower(u)) + ((0.5 * v) * (lower(u) + upper(u))), (sqrt(3) / 2 * (v * (upper(u) - lower(u)))), u, a, b, v, 0, 1) → o
26. Surface(u, (v * upper(u)) + (((1 - v) * 0.5) * (lower(u) + upper(u))), (((sqrt(3) * 0.5) * (1 - v)) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → u
27. Segment(C, U) → i_1
28. Segment(U, G) → j_1
29. Segment(C, G) → k_1