Hello Hans, The macro you wrote to draw the arrows of the vectors does not seem to work anymore. Thank you Fabrice \useMPlibrary[mat] % will be in meta-imp-mat.mkiv \startMPextensions vardef math_stacker_arrow_shape = image ( drawarrow (OverlayWidth,OverlayOffset) -- (0,OverlayOffset) withcolor OverlayLineColor ; setbounds currentpicture to boundingbox currentpicture bottomenlarged (OverlayOffset/2) topenlarged (OverlayOffset/2) ; ) enddef ; vardef math_stacker_leftarrow_shape = math_stacker_arrow_shape enddef ; vardef math_stacker_rightarrow_shape = math_stacker_arrow_shape rotated 180 enddef ; \stopMPextensions \startuniqueMPgraphic{math:stacker:\number"2190} math_stacker_draw(math_stacker_leftarrow_shape) ; \stopuniqueMPgraphic \startuniqueMPgraphic{math:stacker:\number"2192} math_stacker_draw(math_stacker_rightarrow_shape) ; \stopuniqueMPgraphic % so far \setupmathstackers [both] % vfenced] [color=darkred, alternative=mp] \setupmathstackers [top] [color=darkred, alternative=mp] \setupmathstackers [bottom] [color=darkred, alternative=mp] \starttext $\overbracket {a+b+c+d} \quad \underbracket {a+b+c+d} \quad \doublebracket{a+b+c+d}$ \blank $\overparent {a+b+c+d} \quad \underparent {a+b+c+d} \quad \doubleparent {a+b+c+d}$ \blank $\overbrace {a+b+c+d} \quad \underbrace {a+b+c+d} \quad \doublebrace {a+b+c+d}$ \blank $\overbar {a+b+c+d} \quad \underbar {a+b+c+d} \quad \doublebar {a+b+c+d}$ \blank $\overleftarrow {a+b+c+d} \quad \overrightarrow {a+b+c+d} $ \blank $\underleftarrow {a+b+c+d} \quad \underrightarrow {a+b+c+d} $ \blank \stoptext