Browse[1]> Lframe v v v v v v v v 1 8 7 6 5 4 3 2 1 2 9 8 7 6 5 4 3 2 3 10 9 8 7 6 5 4 3 4 11 10 9 8 7 6 5 4 5 12 11 10 9 8 7 6 5 6 13 12 11 10 9 8 7 6 7 14 13 12 11 10 9 8 7 8 15 14 13 12 11 10 9 8 Browse[1]> fdim(Lframe,q=2) Error in slopeopt(AllPoints, Alpha) : Object "LineP" not found thanks for any feed back