# set terminal svg size 600,400 dynamic enhanced fname 'arial'  fsize 10 mousing name "piecewise_3" butt solid 
# set output 'piecewise.3.svg'
set border 16 front linetype -1 linewidth 1.000
set key at screen 0.5, 0.15, 0 center center vertical Right noreverse enhanced autotitles nobox
set style data lines
set noxtics
set noytics
set title "Piecewise function of one parameter in 3D" 
set title  offset character 0, 0, 0 font ",15" norotate
part1(x) = 0.5 + (9.*x-x**3)/ 24.
part2(x) = 1.0 + (x-3.0)**3 / 48.
save_encoding = "utf8"
GPFUN_part1 = "part1(x) = 0.5 + (9.*x-x**3)/ 24."
GPFUN_part2 = "part2(x) = 1.0 + (x-3.0)**3 / 48."
part1 = "part1: for x < 1  norm(x) ≈  ½ + (9x-x^3) / 24"
part2 = "part2: for x > 1  norm(x) ≈   1 +  (x-3)^3 / 48"
h = 15.0
splot [-2:2][-2:2] sample    [h=1:5]   '+' using (cos(h)):(sin(h)):(h),    [h=5:10]  '+' using (cos(h)):(sin(h)):(h),    [h=10:15] '+' using (cos(h)):(sin(h)):(h)