"Jitter" a data point(s) on XY scatter plot

[fouts]

Is there a way to "jitter" two or more identical data points on a XY scatter plot so that they do not completely overlap on the graph?

[MrExcel]

This from Mala Singh who runs the engineering division at MrExcel:

A data point is a data point and we can't 'jitter' identical data
point(s) of two series without modifying the co-ords of the point
for one of the series - and this is something we do not want to do
because that would imply modifying the data series itself.
The best way I can think of is:
Use 'hollow' data markers for each series - i.e. specify
foreground color only and set background color to 'none'. Try to
use a contrasting set of data markers for the series so that one
marker is clearly visible through the other - a possible
combination could be circle for one series and and cross for the
other - all the better if you additionally specify a different
marker size for each series. When you do this the identical points
can be identified easily as those shown with 'combination'
markers.
Mala