impenetrable [Adjective] + wall [Noun]

Strength Strength Dispersion
A:
5
CHISQ:
28.4
AWT:
16,888,087
TTEST:
1.94
G2:
15.78
FAWT:
3.22
MI:
2.91
LOGLOG:
6.76
JD:
0.56
MI3:
7.56
DICE:
0.06
RANGE: