car
.
xy
x
cdr
.
xy
y
.
car
x
cdr
x
x
atom
.
xy
false
car
.
xy
x
cdr
.
xy
y
.
car
x
cdr
x
x
atom
x
false
2.1
true
car
.
xy
x
car
.
xy
car
.
xy
x
x
cdr
.
xy
y
cdr
.
xy
cdr
.
xy
y
y
.
car
x
cdr
x
x
.
car
x
cdr
x
.
car
x
cdr
x
x
x
atom
.
xy
false
atom
.
xy
atom
.
xy
false
false
atom
x
false
atom
x
1
.
car
x
cdr
x
x
atom
.
car
x
cdr
x
atom
.
xy
false
false
kbcv2.0.0.0