Hi, I’have a lot of courses notes in MKII. I’m trying to move to MKIV. I have a problem that I’m not able to resolve, to make a border matrix with brackets. In MKII, I was using a macro, found somewhere, which works great, but no longer works; here is the macro: % Border matrix: first line and column are label \catcode`\@=11\relax \newdimen\p@renwd \font\tenex=cmex10 \setbox0=\hbox{\tenex B} \p@renwd=\wd0 \def\bbordermatrix#1{\begingroup \m@th \setbox\z@\vbox{\def\cr{\crcr\noalign{\kern2\p@\global\let\cr\endline}}% \ialign{$##$\hfil\kern2\p@\kern\p@renwd&\thinspace\hfil$##$\hfil &&\quad\hfil$##$\hfil\crcr \omit\strut\hfil\crcr\noalign{\kern-\baselineskip}% #1\crcr\omit\strut\cr}}% \setbox\tw@\vbox{\unvcopy\z@\global\setbox\@ne\lastbox}% \setbox\tw@\hbox{\unhbox\@ne\unskip\global\setbox\@ne\lastbox}% \setbox\tw@\hbox{$\kern\wd\@ne\kern-\p@renwd\left[\kern-\wd\@ne \global\setbox\@ne\vbox{\box\@ne\kern2\p@}% \vcenter{\kern-\ht\@ne\unvbox\z@\kern-\baselineskip}\,\right]$}% \null\;\vbox{\kern\ht\@ne\box\tw@}\endgroup} \catcode`\@=12\relax but MKIV gives me the error: \bbordermatrix #1->\begingroup \m@th \setbox \z@ \vbox {\def \cr {\crcr \noa... l.26 i & j & k & l \cr} 16 \null\;\vbox{\kern\ht\@ne\box\tw@}\endgroup} 17 \catcode`\@=12\relax I look for solutions on the list, but did not find anything.Here is a minimal example: \starttext A border matrix: \startformula \bbordermatrix{ a & b & c & d \cr e & f & G & h \cr i & j & k & l \cr} \stopformula \stoptext As I have in my notes hundreds of such matrix, it is really difficult to change the input format. Do you know, or can you point me, to a solution ? I’m in a dead end.. Thanks a lot. F.