Hi, compiling example with quadriliterals and \startMPdefinitions{solvers} \stopMPdefinitions from MetaFun manual, regardless of the code that is commented out inside MPdefintions environment, gives: ! You can't use `\relax' after \the. system > tex > error on line 30 in file solvers.tex: You can't use ` ... 20 % z1=0.5[z11,z13] ; z2=0.5[z21,z23] ; 21 % z3=0.5[z31,z33] ; z4=0.5[z41,z43] ; 22 % draw z1--z3 dashed evenly ; draw z2--z4 dashed evenly ; 23 % z0=whatever[z1,z3]=whatever[z2,z4] ; 24 % mark_rt_angle (z1,z0,z2); 25 % if show_labels>0: 26 % draw_problem_labels ; 27 % fi; 28 % endgroup ; 29 % enddef ; 30 >> \stopMPdefinitions 31 32 \starttext 33 %a 34 \stoptext <recently read> \@MPF@::solvers \dostartMPdefinitions ...er {\the \MPinstancetoks #2} l.30 \stopMPdefinitions Is this a bug? Vedran