I saw something interresting in a spreadsheet of somebody. The spreadsheet
contained a table with a certain value in for instance cell D5.
The contents of cell D5 was used somewhere in the sheet to perform several
calculations.
To create different situations one would change the value in cell D5.
Underneath cell D5 I saw a slide-bar. Putting the mouse over this slidebar
a Hand appeared (like a Macro was assigned to it).
With the Hand I could move the slide left and right and the value in D5
would change with the position of the slide.
The creator of this sheet is not known by the person who used it.

I would like to use this feature in some of my own sheets.
How can I create something like this?

Ricky