[plt-scheme] consing returned vectors

> You're not seeing a vector represention on screen.  Rather, you're 
> seeing the "shared structure".  See:
>
> http://download.plt-scheme.org/doc/360/html/mzscheme/mzscheme-Z-H-11.html#node_sec_11.2.5.1
>
> for more details.

Just wanted to add: "Showing sharing in values" isn't enabled by default. 
At least, it shouldn't be.  Let's double check this.

>From DrScheme, if you go into the "Language" menu, and then into "Choose 
Language...", and then if you press the "Show Details" button on the 
bottom of the dialog box, then you should see a checkbox there with the 
label: "Show sharing in values".  Is it checked or unchecked?