you can't multiplex sprites so that more than 8 appear on the same line.
the secret is to pretend you have a 9th sprite by emulating it with characters that look exactly like one of the sprites would.
the secret is to pretend you have a 9th sprite by emulating it with characters that look exactly like one of the sprites would.
The borders are open when you can still do the normal multiplexing, because there's lots of vertical separation between the sprites.
Later, when they put the sprites together on the same line, the borders are closed.