set arrow from 80,-2 to 80,2 nohead ls 2
set arrow from 80,6 to 80,10 nohead ls 2
set arrow from 80,14 to 80,18 nohead ls 2
set arrow from 80,22 to 80,26 nohead ls 2
set arrow from 80,30 to 80,34 nohead ls 2

plot '-' with linespoints smooth csplines
 80  -5
 90  15
100 -20
e