I, Makoto Tatsuta, have updated my proof figure macros proof.sty so that it can be used for not only LaTeX 2.09 but also LaTeX 2e.
This package helps you to write proof figures used in mathematical logic easily and beautifully. Many logicians and computer scientists have been using this package since I wrote this package in 1990. Files:
The usage is given in the comments in the head of proof.sty. The output of proofeg.tex will also explain how to use the macros.
Note that a large proof figure often requires bigLaTeX instead of usual LaTeX because of its capacity.
They can be downloaded here. The size is small (about 10K bytes).