Xtop 7 highest

.subckt highest HH
X4 HH higher
RD HH HH 12k
.ends

.subckt higher h
X3 h medium
.ends

.subckt medium m
X2 m low
.ends

.subckt low L
X1 L lowest
.ends

.subckt lowest LL
RLL LL LL 12k
.ends

