a__zeroscons0zerosa__andttXmarkXa__lengthnil0a__lengthconsNLsa__lengthmarkLmarkzerosa__zerosmarkandX1X2a__andmarkX1X2marklengthXa__lengthmarkXmarkconsX1X2consmarkX1X2mark00markttttmarknilnilmarksXsmarkXa__zeroszerosa__andX1X2andX1X2a__lengthXlengthX2.1a__lengthconsNzerosa__lengthconsNLsa__lengthmarkLsa__lengthmarkzeros11markzerosa__zerossa__lengtha__zeros11a__zeroscons0zerossa__lengthcons0zerosN0sttt21.14if standard then (var | con | (lpo || unfold[1] || (dp;(tdg | sccs | sc)*;(edg[2] | sccs | sc | sct | {ur?;lpo -dp -af[2]}restore | {ur?;matrix -dp -dim 2 -ib 2 -ob 2 -ur[2]}restore | uncurryx?;uncurryx -top )[10]*)!)) else if relative then (trivial | var | (unfold[2] || (( lpo -quasi | matrix -dim 2 -ib 2 -ob 3 | matrix -dim 3 -ib 2 -ob 2 | uncurryx )[10]*))) else fail