- 'data.csv' using 1:3 every ::1 with lp title "systolic", \
- 'data.csv' using 1:4 every ::1 with lp title "diastolic" , \
- 'data.csv' using 1:5 every ::1 with lp title "pulses"
+ 'data.csv' using (stringcolumn(1).'-'.stringcolumn(2)):3 every ::1 with lp title "systolic", \
+ 'data.csv' using (stringcolumn(1).'-'.stringcolumn(2)):4 every ::1 with lp title "diastolic", \
+ 'data.csv' using (stringcolumn(1).'-'.stringcolumn(2)):5 every ::1 with lp title "pulses"