Is it possible to change a cell color through conditional formatting (or some other method) to have a cell color change when it's cell's location is used in a formula of a different cell.

A quick example:

Cell A2 would change to red if a formula was typed into cell A3 that referenced the cell A2.

I am doing a lot of Boolean logic AND / OR statements and would like to keep track of the bits that I have already used. I already use the "Trace Precedents" tool in Excel, but think this color changing would help greatly if possible.

Thanks!
John