I looked up, slightly amazed... There was a car? suspended
between the walls of the alley, above me.
I was still gawking at it when a woman's voice beside me
said, "Would you like a ride? I parked it up there, because
it's free."
She pressed a button on a remote controller and the
vehicle
scooted down the two walls, shot forward a few
metres, to avoid a pair of rubbish bins, and settled gently
to the ground in front of us.
It appeared to have wheels on each of the three visible
sides, one on each corner of its surface. Well, not wheels,
but rounded rubber surfaces, four apparent on each of the
six sides of the cubic vehicle and caged somehow into the
corners of the vehicle.
"Holonomic wheels, driven by electric motors," she
explained.
A panel opened in one of the flat surfaces and the woman
stepped inside, settling into one of the two seats,
motioning me to the other.
An engine came to life under the seats, and the "door" slid
closed. The panels were clear from in here, though they
had looked like deep maroon mirrors from the outside.
She pressed four buttons on the touchscreen in front of
her, and the "car" began rolling forward, faster as she
pressed on the control yoke. Then, something happened! I
was aware of the lateral pressure of the seat against my
left side, and I realised we had just made a 90 degree
turn, without swinging through the normal arc a car might.
All I heard was a series of quick mechanical noises, as the
electric drivemotors (balls, wheels... whatever, I was still
struggling to grasp those...) changed the direction of
application of the "wheels".
The driver explained it thus: The engine drives 24 of these
powerful little electric motors, running off a hybrid-fuelled
generator that comprises the engine. She explained that
the pressure sensors in the control yoke direct a computer
to figure out which wheels are best to use, and which two
of the three drivemotors in contact with each wheel (think
of a giant mouseball) are best to propel the car in the
desired direction.
The seating/engine module was apparently mounted in a
giant gimbal.
"If it tips over, it just engages the two new wheels now in
contact with the ground, while the seating position
remains horizontal", she explained.
The wheels can be extended outwards, to increase ground
clearance, using some of the suspension travel to allow
this.
Apparently, the trick in the alley was possible as all eight
wheels were in contact with the walls, simultaneously.
The suspension travel trick made "chimneying" possible in
narrow spaces.
A continuously variable transmission that could be geared
to a final drive ratio from almost 75:1 up to 2:1 made it
possible to go almost anywhere.
Four-wheeled, or even six-wheeled cars suddenly seemed
so passe.