clear;
close all;

y1 = [1.8 2 1.5 1.5 2.5; 2.5 1.7 1.5 2 1.5];
d = [2 1.24 0.59 1.31 1.44];

x = linspace(0,3);
y = linspace(0,3);
[X,Y] = meshgrid(x,y);
Z = zeros(100,100);
% Z = (norm([x; y] - y1(:,1))^2 - d(:,1)^2)^2;

for i = 1:100
for k = 1:100
    for j = 1:5
        Z(i,k) = Z(i,k) + (norm([X(i,k); Y(i,k)] - y1(:,j))^2 - d(j)^2)^2;
    end
end
end

figure
contour(X,Y,Z,50)