clear all
close all

z = [  0  0  0  0;  5    5    5  5; 10  10  10  10; 15 15 15 15];
x = [-10 -5  5 10; -8 -4.5  4.5  8; -6  -4   4   6; -6 -4  4  6];
y = [  0 -3 -3  0;  0 -2.2 -2.2  0;  0  -2  -2   0;  0 -2 -2  0];

tx = -10:0.1:10;
tz =   0:0.2:15;
[ZI,XI] = meshgrid(tz,tx);
YI = griddata(z,x,y,ZI,XI);
mesh(ZI,XI,YI);