When you plot things in Matlab, the most recently plotted data series is placed on top of whatever's already there. For example:

```
figure; hold on
plot(sin(linspace(0,pi)),'linewidth',4,'color',[0 0 1])
plot(cos(linspace(0,pi)),'linewidth',4,'color',[1 0 0])
```

Here, the red line is shown on top of the blue line (where they intersect). Is there any way to set "how deep" a line is drawn, so that you can plot things *beneath* what's already there?