Okapi is a under-graduation OOP little project, about making graphics with real numbers. I'm not going to talk too deep about it, by now, but, in a nutshell, it can produce colored bar, box, line, dot and pie-like graphics. Greatly inspired on some R language features, It's built mainly under regular expressions, Java Swing and Java Reflection.
For further details, see the official documentation (in Portuguese): https://github.com/FelSiq/okapi/blob/master/Okapi-doc-oficial.pdf