Because she wrote answer x without space as a concern, thinking she had the right answer already, then she realized "oh crap, it's answer y, I wish I would have left more room?"
I agree 100%. But that's exactly my point.
The space she'd pretty much filled, and then squeezed another answer in tiny letters along the edge of, was very clearly a wide, short rectangle, just like what we see at home. Had it been otherwise, she'd never have written it that way, or even have been *able to* see where the bottom edge of our view would be. It was very clearly not scrunched electronically to fit or anything along those lines. (It was also the most painful to see loss of its kind that I can remember... but that's another matter.)
That's evidence (though not, of course, *absolute* proof) that the answer box (however it may be presented) really is that shape, about equivalent to the top third of a monitor. Countless episodes show the same, and not one (so far as I've seen, though I admit I've only seen about a third of the episodes since discovering the show in the summer of 1986) shows otherwise.
(And I cannot express how weird this conversation feels. It feels the same as if I'd asked why there are so many flashing lights on the Price is Right set, only to hear everyone say there are none at all.)