Not in parallel, but sequentially. The sale of a given scratchoff goes on for a period of time, after which no more are sold, although prizes can be claimed for a given number of months. A new series is then started under basically the same name with the same rules, so people who always buy a certain name of scratchoff ticket can buy what they are used to.
One of the thing that was done to keep peoples’ interest is the top prize drawing. They basically offer two of the top prize. One is a direct win by scratchoff, the other when scratched off shows “TPD” for top prize drawing. In other words, not the top prize, but a chance at the top prize, and there can be more of those given out than the one direct scratchoff prize. It loses the instantaneous win, which is what attracts people to scratchoffs, but people can feel that they still have a chance at the top money.
The format that the OP was talking about was ticket with two scratch areas. One side is a free big mac, and one side has nothing. You only win if you guess right, and you’re only allowed to scratch off one side.
I seem to remember something (perhaps in one of the Big Secrets books) about how someone figured out the patterns to the scratch-off cards for some corporate contest. Imagine that the contest involved scratching out only three spots in a three-by-three matrix to complete a row or column in a tic-tac-toe game. As I recall, after scratching a bunch of cards, the person figured out how to predict the correct order to scratch off the spots, after exposing the first one.