I've been figuring for this quite some time. Hope someone can help me out.
I can construct a...
valid union of vectors using very basic movements (black and grey moves 90° back and forth, yellow and purple moves 135°, blue moves 90° and red moves 45°).
This leads to
The solution is probably not unique, but this is one which maps to the set possible solutions.
Reading either top to bottom or left to right, if two diagonals are present, keep them, otherwise nothing. If exactly one straight is present, keep it, otherwise nothing. That is, the diagonal's are AND'd and the straights are XOR'd.