Philips Magnavox Videogames and the Entertainment Revolution Trigger Happy - Manual (Page 206)

Trigger Happy
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invented to gild the cage, and then burst its bars
completely.
“Wraparound” screens were soon developed, as in
Asteroids (1979), where the player’s ship could, rather
than bouncing off the screen edges, travel off one side
of the screen and magically reappear on the other,
providing increased fluidity of action. Now space was
curved. Your disappearing ship would sail “over” the
top and zip around the (imaginary) back
instantaneously before coming “under” and
rematerializing at the bottom. Topologically, the spatial
arrangement of Asteroids, though it looked flat, was
actually equivalent to the surface of a torus (a doughnut
with a hole in the middle). While this curvature
afforded the player greater freedoms of
maneuverability, it also cunningly increased the sense
of entrapment. For anyone who has watched their
Asteroids ship career repeatedly across the screen time
after time at full speed knows that there is no escape,
however far you travel, from the implacable boulders.
The superficial limits of the screen were further
eroded by the invention of scrolling. The term was
borrowed, with semi-conscious irony, from that
precodex literary technology, the scroll, which may be
unfurled horizontally or vertically, according to the