1] build expression: 5 -> [5]
hi
2] build expression: 10 -> [10]
3] build block     : [[10]] -> [10]
[10]
[5]
4] build expression: 22 -> [22]
5] build block     : [[22]] -> [22]
6] build 2nd       : [22] -> [22]
7] build block     : [[22]] -> [22]
[22]
level: 1, 2nd
level: 2, 2nd
level: 3, 1st
8] build expression: 33 -> [33]
9] build block     : [[33]] -> [33]
10] build 1st       : [33] -> [33]
11] build block     : [[33]] -> [33]
12] build 2nd       : [33] -> [33]
13] build block     : [[33]] -> [33]
14] build 2nd       : [33] -> [33]
15] build block     : [[33]] -> [33]
[33]
level: 3, 1st
16] build expression: 43 -> [43]
17] build block     : [[43]] -> [43]
18] build 1st       : [43] -> [43]
19] build 2nd       : [43] -> [43]
20] build block     : [[43]] -> [43]
[43]
21] build expression: 51 -> [51]
22] build block     : [[51]] -> [51]
23] build optional  : Optional([51]) -> [51]
24] build block     : [[51]] -> [51]
[51]
25] build expression: 101 -> [101]
26] build block     : [[101]] -> [101]
27] build expression: 102 -> [102]
28] build block     : [[102]] -> [102]
29] build expression: 103 -> [103]
30] build block     : [[103]] -> [103]
31] build array     : [[101], [102], [103]] -> [101, 102, 103]
32] build block     : [[101, 102, 103]] -> [101, 102, 103]
[101, 102, 103]