UGLY TheCollection Intersection year 1973 NICE TheCollection Intersect

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
UGLY:
TheCollection:
Intersection
/ \
[1, 2, 3] year <= 1973
NICE:
TheCollection:
Intersection
/ \
SelectedPinkFloyd year <= 1973
SelectedPinkFloyd:
[1, 2, 3]