What makes you think the individual frames look like the letters? They certainly don't have to. At the price of a little flickering you could, say, show the top

What makes you think the individual frames look like the letters? They certainly don't have to. At the price of a little flickering you could, say, show the top half of the letters in one frame, the bottom half the next, the right half the next and so on. Or randomly leave out one letter in every frame. Or even throw in different replacement letters for one frame each.