X,Y=meshgrid2(-1:0.5:1,-1:0.5:1)
z=sqrt.(X.^2+Y.^2)exp(1imatan.(Y,X))
Z=log.(z)
for k=0:3
Z=Z+1im2pi;
fig=figure()
ax=subplot(;projection="3d")
mesh(ax,X,Y,real(Z))
hold("on")
xlabel("X")
ylabel("Y")
zlabel("lnz")
end