I am composing a Beamer presentation, and I would like to underline some mathematical entities for emphasis.
I am aware of the ulem package, however for a presentation I would like something more visually pleasing, and I was thinking about a felt-tip marker effect, bold and slightly irregular, along these lines:
or also
I must be able to underline just parts of a mathematical expression.
Is there any package I can use to achieve such an effect?

