blkarray -- extensions and modifications of tabular support This package is even less supported than any of David Carlisle's other packages. It was written a long time ago, and is still documented using the conventions of LaTeX2.09 (although it appears to work with current LaTeX releases). In 2014 it had a minor update to work with LaTeX2e font initialisation and in 2015 a second update to avoid a clash with amsmath's use of box0. Apart from these couple of lines all the code dates back to 1992 and was more of a thought experiment than production code. However people seem to find uses for it. It is not really a package for using in documents in its present state, but if you are interested in coding tables of various sorts in TeX, you may be interested to experiment with it...