% threshold testing (r is narrow)

\setupbodyfont[euler,24pt]

\startTEXpage
    $\vec{r}  \ruledhbox{r}$.
    $\vec{\i} \ruledhbox{\i}$.
    $\vec{a}  \ruledhbox{a}$.
    $\vec{m}  \ruledhbox{m}$.
\stopTEXpage
