Drawing a function box with 2 inputs and 2 outputs in LaTeX

[Dragonfall]

I want to have a picture of a box that depicts a function F that takes 2 inputs and 2 outputs with arrows, like-->| F | <--
<--|__| -->

Can I do it with latex code, or do I need to draw a picture?

 

[DrClaude]

What you want seems simple enough that you can use the picture environment: http://en.wikibooks.org/wiki/LaTeX/Picture