This indicator splits volume into buyer volume and seller volume, and a visualization of the volume pressure is drawn with overlaying histograms.

The indicator was initially part of trading software called "Amibroker". It was discussed on the forum, and was initially requested to be converted to mql4, however I decided to convert it to mql5 with my best understanding of the original indicator.

https://www.mql5.com/en/forum/177976/page2#comment_4348326

While I am the author of this mql5 conversion, I credit the original author Nick Molchanoff in the code who came up with the original design.