from
X
cons
X
n__from
n__s
X
head
cons
X
XS
X
2nd
cons
X
XS
head
activate
XS
take
0
XS
nil
take
s
N
cons
X
XS
cons
X
n__take
N
activate
XS
sel
0
cons
X
XS
X
sel
s
N
cons
X
XS
sel
N
activate
XS
from
X
n__from
X
s
X
n__s
X
take
X1
X2
n__take
X1
X2
activate
n__from
X
from
activate
X
activate
n__s
X
s
activate
X
activate
n__take
X1
X2
take
activate
X1
activate
X2
activate
X
X
from
1
cons
2
n__from
1
n__s
1
head
1
2nd
1
activate
1
take
2
0
0
nil
0
s
1
n__take
2
sel
2
FULL