sorting once again

hello there,

for each row i try to create lines in the pattern

line(0to1)

line(0to1)

line(1to2)

line(1to2)

line(2to3)

line(2to3)

line(3to4)

line(3to4)

line(4to5)

line(5to5)

line(5to6)

line(6to7)

line(7to8)

ine(8to7)

then via flip matrix the other orientation, to finally get for everey point 4 lines (forming a cross) except for the border(3lines) and corners(2lines)

i have managed to establish  some logic but now im stuck,

maybe u have a look at the def.

thank you