A Tool to practice Categories / Allegories

Question

Is there any handy tool to practice Categories / Allegories, in the sense that for a defined Category, it is possible to check the result of an operation application.

For example, a tool which provides me a (preferably visual) result of pullback/pushout operation application over the specified sets and relations in Rel Category.

Thanks

Answer 1

Very quick answer, since i am on a satelite connection (very expensive). Here you have an interactive tool for the category of finite sets. Wildcats is my (free) package for Mathematica which can be used to do some calculations and visualizations in category theory.

Answer 2

GDCD is is another Tool for practicing CAT theory (here is the link)