grid_move_lines
grid_move_lines(gd, rupper, rupper + 1, rlower - rupper, bg);
grid_move_lines(gd, rupper + 1, rupper, rlower - rupper, bg);
grid_move_lines(gd, py + ny, py, sy - py - ny, bg);
grid_move_lines(gd, rlower + 1 - ny2, py, ny2, bg);
grid_move_lines(gd, py, py + ny, sy - py - ny, bg);
grid_move_lines(gd, py, py + ny, ny2, bg);
void grid_move_lines(struct grid *, u_int, u_int, u_int, u_int);