Modeling potential flow over rankine oval

There is no errors with the code, but when plotting a blacked out plot comes up. Not sure what the issue is but I appreciate any help.

clc;
clear all;
m=25;
U = 1;
a=5;
%Mesh for fourth quadrant and corresponding stream value function
[X1,Y1] = meshgrid(.05:.1:30,-30:.1:-.05);
psi1 = U*Y1*atan2(2*a*Y1, X1.^2+Y1.^2-a^2);
%Mesh for first quadrant and corresponding stream value function
[X2,Y2] = meshgrid(.05:.1:30,.05:.1:30);
psi2 = U*Y2*atan2(2*a*Y2, X2.^2+Y2.^2-a^2);
%Mesh for second quadrant and corresponding stream value function
[X3,Y3] = meshgrid(-30:.1:-.05,.05:.1:30);
psi3 = U*Y3*atan2(2*a*Y3, X3.^2+Y3.^2-a^2);
%Mesh for third quadrant and corresponding stream value function
[X4,Y4] = meshgrid(-30:.1:-.05,-30:.1:-.05);
psi4 = U*Y4*atan2(2*a*Y4, X4.^2+Y4.^2-a^2);
figure (1)
A='on';
B = 2;
C = 2.5;
contour(X1,Y1,psi1,'k','showtext',A,'textstep',B,'levelstep',C);
hold on;
contour(X2,Y2,psi2,'k','showtext',A,'textstep',B,'levelstep',C);
hold on;
contour(X3,Y3,psi3,'k','showtext',A,'textstep',B,'levelstep',C);
hold on;
contour(X4,Y4,psi4,'k','showtext',A,'textstep',B,'levelstep',C);
hold off;
xlim([-30 30]);ylim([-30 30]);
xlabel('X');ylabel('Y');
grid on;