Hello, Everything is in the title, as this example shows. Thanks, Fabrice #################################################################### \usemodule[tikz] \usetikzlibrary[matrix] \setupbodyfont[pagella,11pt] \starttext \starttikzpicture \matrix [matrix of math nodes,ampersand replacement=\&] { a_8 \& a_1 \& a_6 \\ a_3 \& a_5 \& |[red]| a_7 \\ a_4 \& a_9 \& a_2 \\ }; \stoptikzpicture \stoptext #################################################################### tex error > tex error on line 14 in file /home/fab/ntg49.tex: ! Argument of \tikz@lib@matrix@with@options has an extra } <inserted text> \par <to be read again> } l.14 } ; 4 \setupbodyfont[pagella,11pt] 5 6 \starttext 7 8 \starttikzpicture 9 \matrix [matrix of math nodes,ampersand replacement=\&] 10 { 11 a_8 \& a_1 \& a_6 \\ 12 a_3 \& a_5 \& |[red]| a_7 \\ 13 a_4 \& a_9 \& a_2 \\ 14 >> }; 15 \stoptikzpicture 16 17 \stoptext