Temporal Thought Experiments II

Now imagine a second 3-panel comic strip, Strip 2, directly under the first, Strip 1. The two strips are identical except that in Strip 2, panel 3, B's speech balloon reads not "Ha! Ha! Ha!" but "That's not funny!" It is easy to see Strips 1 and 2 as two parallel timelines. However, if there is an observer whose temporal dimension runs down the page, then that observer perceives Strip 2 not as paralleling but as succeeding Strip 1. He thinks that Strip 1 either has ceased to exist or has been transformed into Strip 2. 

But:

at no moment in the timeline of Strip 1 does Strip 1 either cease to exist or metamorphose into Strip 2;

readers of the page displaying the two strips continue to see both strips, one above the other.

Imagine instead that, some time after drawing Strip 1, the artist erases "Ha! Ha! Ha1" and replaces it with "That's not funny!" in panel 3. Now Strip 2 has succeeded Strip 1 not as perceived by an observer whose temporal dimension runs down the page but in the temporal dimension of the artist himself. To the characters in Strip 2, the events of Strip 1 never happened but, to the artist, Strip 1 did exist and, in panel 3 of that strip, B did laugh. Contradictions arise only when we confuse sequences of events in different temporal dimensions.