Maybe some examples will help:
This will restore the left half of the screen (assuming the default 608 X 352 view):
#restorescreen(1,1,304,352,1,1)
This will restore the right half:
#restorescreen(304,1,608,352,304,1)
This will draw the left half on the RIGHT side of the screen (I actually haven't found a use for anything like this so far, maybe with a menu or something):
#restorescreen(1,1,304,352,304,1)