data trans0.dat
read x 1
read y 4
data trans1.dat
read x1 1
read y1 4
data trans3.dat
read x3 1
read y3 4
set rat1 = y1/y -1
set rat2 = y3/y -1
set lx = lg(x)
limits -3 2 -0.1 0.1
ctype green
connect lx rat1
ctype red
connect lx rat2
ctype default