When I run this example with mpost amd mptopdf, everything is fine. But running it with context mkiv, using its mplib I get an error. The problematic command is dotlabels.top(0,1,2,3,4,5,6); Commented it out, then it works with context, too. Herbert ------------------------------------------------------ [...] systems : begin file latex5 at line 1 mplib : initializing instance 'metafun' using format 'metafun' mplib : loading 'metafun.mp' (experimental metapost version two) mplib > mp terminal: ! Redundant equation. <to be read again> ; <*> ...caled 0.2in yscaled 0.08 rotated 30; u=4cm; path p; x0=x3=x4; z1-z0=0... mplib > mp error: unknown, no error, terminal or log messages mplib > mp terminal: [1] [...] ------------------------------------------------------- \starttext \startMPcode pickup pencircle scaled 0.2in yscaled 0.08 rotated 30; u=4cm; path p; x0=x3=x4; z1-z0=0.5in*dir 30; z2-z3=whatever*(z1-z0); z6-z5=whatever*(z1-z0); z1-z6=1.2*(z3-z0); rt x3=lft x2;x5=0.55[x4,x6]; y4=y6; lft x3=bot y5=0; top y2=1in; draw z0--z1--z2--z3--z4--z5--z6 withcolor .7white; dotlabels.top(0,1,2,3,4,5,6); \stopMPcode \stoptext