tank treads for pot.holes

11.25: gear/tank-based pothole negotiation:
. for pot holes use an attachment that is like tank treads:
like a ski foot used by a snowmobile for steering
except it's an inline skate (a series of skate wheels)
with a tread belt around them;
so when the skate catches the edge of a pothole,
that edge doesn't get lodged between wheels .
. the skate is mounted on the front wheels
in either of 2 positions:
. if there is snow, sand, etc to steer on,
then it's being pressed flat on the ground
to steer the way ski-mobile does .
. if there is pavement or rocks,
then its lifted and angled,
so as to act like the tank's treads .