How do I create an adoptable path?

Im trying to make an ant game.

dualproject.it/test/ant

In the example you can click on the red ant (red can dig) and make a path.

when the red ant had finished the path, the blue ant had to use only that course to move. In the example i use that system.

1) red ant selected and click on a map, the red ant will move and place wall on the side and also place hole sprite behind.

2) when the red ant stop move, spawn wall in front.

3) the blue ant is selected (check that the red ant is not moving), on click on the map (only the click on the hole sprite are allowed), blue ant calculate path and the only path possible will be the before created path.

my question: there are a better way? without wall at the side of the red ant?

Ok, now I see.

You can try to remove the obstacles for the blue ant where the red ant walked ahead, instead of adding new objects.

So this also fixes the problem blue cant walk while red does.

Hope this helps.

oky but i dont understand how :P

I'll had to place obstacle everywhere, for ex a grid of solid sprites and destroy on collision with red ant? this would not be more heavy for the system?

i guess not, since you dont need to add walls etc anymore.