I can clearly hear when the tone loops, so I don't really get what's the illusion. So it is as "impossible" to hear the beginning or the end of the given scale

I can clearly hear when the tone loops, so I don't really get what's the illusion. So it is as "impossible" to hear the beginning or the end of the given scale as it is "impossible" to see when the two pictures begin and start to fade in and out.