static struct coord_def prev_explore_target = coord_def(-30000, -30000);

    prev_explore_target = coord_def(-30000, -30000);

    prev_explore_target = target;

        // other and the two previous explore targets are close to each
        // other, then we're probably zigzaging.

        // other.

            && (abs(prev_travel_moves[1] - prev_travel_moves[0]) % 4) == 2
            && grid_distance(prev_explore_target.x, prev_explore_target.y,
                             whereto.x, whereto.y) <= (LOS_RADIUS + 1))

            && (abs(prev_travel_moves[1] - prev_travel_moves[0]) % 4) == 2)

                set_target_square(target);
                return;

                // Auto-explore is only zigzagging if the prefered
                // target (whereto) and the anti-zigzag target are
                // close together.
                if (grid_distance(target.x, target.y,
                                  whereto.x, whereto.y) <= 5
                    && (distance(target.x, target.y,
                                 whereto.x, whereto.y) <= 34))
                {
                    set_target_square(target);
                    return;
                }

            else
                anti_zigzag_dir = -1;

            anti_zigzag_dir = -1;

        auto-explore.  In most circumstances this will increase the
        number of turns spent to auto-explore an entire level by
        less than 1% (with a 2% increase the maximum), but with
        a 7% to 13% increase in the Shoals and in city-type levels
        such as those found in the Vaults.

        auto-explore.  On average it increases the number of turns taken
        by about 0.9%, sometimes actually speeding it up slightly and
        sometimes increasing the turns taken by up to 5%, with
        pathological cases causing a 50% increase.