clf;
clear;
rect=[0.1,0.3,0.85,0.68];%lower left x and y, width,height
axes('Position',rect);
caxis([0 1]);
colormap gray;
%
ny=9;nx=12;x=linspace(0,1,nx);y=[1 0.999 0.55 0.549];y=[-y 0 fliplr(y)];
% define sides of basin
h=[0 0.45 0.45 1];h=[h 1 fliplr(h)];H=[-h;-h]';
surf([0 1],y,H,ones(size(H)));% draw in black
hold on
% draw surface
for ky=1:ny
  eta(ky,:)=0.1*sin(3*x);
  if(abs(y(ky))>0.55)
    eta(ky,:)=eta(ky,:)+0.2*sin(10*x);
  endif
end
mesh(x,y,eta,0.1*ones(size(eta));% draw in gray