S.Plouffe>or worst : ImplicitRungeKuttaLobattoIIIBCoefficients < Several versions back, NeilB found the longest name to be MultivariateHypergeometricDistribution But the Predictive Interface will save you typing this. Thane> For example something like this subsets[list_] := Distribute[Map[{{},{#}}&,list], List, List, List, Union] gives me a headache to even look at. < That's unacceptably transpicuous! subsets[list_] := Distribute[{{},{#}}&/@list, List, List, List, Union] Of course, the installed function Subsets offers this, plus a bewilderment of bells and whistles. Looking in my toolbox, e.g., Brill2sqs[p_Integer] := NestWhile[{#[[2]], Mod @@ #} &, {p, #}, #1[[1]]^2 > p &] & /@ Select[#[[1, 2]] & /@ Solve[z^2 == -1, Modulus -> p], # < p/2 &] But what I *always* get wrong is the semantics of Sequence, e.g. st0[{f_, n_, M_?MatrixQ, cf___}] := Block[{xy = Divide @@ M, t}, If[Floor@xy[[1]] == (t = Floor@xy[[2]]), Join[{f, Sow[n]}, {{{0, 1}, {1, -t}}.M, Sequence @@ {cf, t}}], xy = M.f[n]; {f, n + 1, xy/GCD @@ Join @@ xy, cf}]] And nearly always get wrong: Hold, ReleaseHold, HoldPattern, Verbatim, Unevaluated, plus the rules for the spontaneous disappearance of wrappers, e.g. MatrixForm. It's a baroque language, at once too terse and too verbose. Perhaps unavoidable consequences of an *enormity* of functionality. One of the kids tells me "Version 10 is great!" Despite having grown only 800 functions since Version 9. --rwg