diff --git a/latex/yssymbols.sty b/latex/yssymbols.sty
index bdf2540..4011fc0 100644
--- a/latex/yssymbols.sty
+++ b/latex/yssymbols.sty
@@ -44,7 +44,7 @@
 \def\sem#1#2{{\left\lbr#1\right\rbr}_{#2}}
 \NewNegationCommand\models{\mathrel{\notaccent\models}}
 
-\def\metab#1{\ensuremath{\langle #1\rangle}}
+\def\metab#1{\ensuremath{\fbox{$#1$}}}
 \def\metasyn#1{\metab{\tmit{#1}}}
 
 \newenvironment{specification}{\vskip-\lastskip\ \par\begin{mdframed}[skipbelow=1ex]\begin{description}}{\end{description}\end{mdframed}}