哪些四边形是平行四边形？

GeoGebra 命令及参数

1. Segment(A, B) → AB
2. OrthogonalLine(B, AB) → b
3. OrthogonalLine(A, AB) → c
4. Point(c) → C
5. OrthogonalLine(C, b) → d
6. Intersect(d, b) → D
7. Segment(A, C) → AC
8. Segment(C, D) → CD
9. Segment(D, B) → DB
10. Angle(A, C, D) → α
11. Angle(C, D, B) → β
12. Angle(B, A, C) → γ
13. Angle(D, B, A) → δ
14. Slope(AB) → a
15. Slope(AC) → e
16. Slope(CD) → f
17. Slope(DB) → g
18. Segment(E, F) → h
19. Circle(E, F) → k
20. Circle(F, E) → p
21. Point(k) → G
22. Segment(E, G) → i
23. Circle(G, E) → q
24. Intersect(p, q) → H, I, ,
25. Segment(G, I) → j
26. Segment(I, F) → l
27. Slope(h) → m
28. Slope(i) → n
29. Slope(j) → o
30. Slope(l) → r
31. Segment(J, K) → s
32. Circle(K, J) → t
33. Point(t) → L
34. Segment(K, L) → a_1
35. Segment(J, L) → b_1
36. OrthogonalLine(K, b_1) → c_1
37. Point(c_1) → M
38. Segment(J, M) → d_1
39. Segment(L, M) → e_1
40. Slope(s) → u
41. Slope(a_1) → v
42. Slope(e_1) → w
43. Slope(d_1) → f_1
44. Angle(E, F, I) → ε
45. Angle(F, I, G) → ζ
46. Angle(G, E, F) → η
47. Angle(I, G, E) → θ
48. Angle(J, K, L) → ι
49. Angle(K, L, M) → κ
50. Angle(L, M, J) → λ
51. Angle(M, J, K) → μ