p1 = plot(v_4 + 0 , y_4 ,'r', 'linewidth', 2); hold on;
p2 = plot(v_6 + 6 , y_6 ,'g', 'linewidth', 2);
p3 = plot(v_10 + 10, y_10,'b', 'linewidth', 2);
p4 = plot(v_15 + 15, y_15,'k', 'linewidth', 2);
p5 = plot(v_19 + 19, y_19,'m', 'linewidth', 2);
ylabel('y/h');
xticks([0 6 10 15 19]);
annotation('textbox',[.37 .3 .6 .6],'String','4' ,'FitBoxToText','on', 'LineStyle','none');
annotation('textbox',[.52 .3 .6 .6],'String','6' ,'FitBoxToText','on', 'LineStyle','none');
annotation('textbox',[.60 .3 .6 .6],'String','10','FitBoxToText','on', 'LineStyle','none');
annotation('textbox',[.73 .3 .6 .6],'String','15','FitBoxToText','on', 'LineStyle','none');
annotation('textbox',[.83 .3 .6 .6],'String','19','FitBoxToText','on', 'LineStyle','none');