Attachments: ques.png (804.6 KB)
for (int i = 0; i < npoints(0); ++i) { vector prev_pos = point(0, 'P', i - 1); setpointattrib(0, 'prev_pos', i, prev_pos, 'set'); }
v@prev_pos = point(0, 'P', @ptnum - 1);
Attachments: prev_pos.jpg (39.7 KB)