The trajectory from the SN where the rifle and shells were found and the witnesses stated the shots came from is the only valid trajectory ever presented. The only mystery in this is why continually present made up theories that are not even remotely possible.
And people wonder how there can be a Flat Earth Society in our day. Are you aware that there are two very different SN-to-head trajectories, i.e., the WC's and the HSCA's? Which one do you accept?
The WC experts said the bullet struck JFK's head "slightly above" and 2.5 cm (1 inch) to the right of the external occipital protuberance (EOP). (Finck indicated to the HSCA that "slightly above" was 1 cm, or 4/10ths of an inch.) But the Clark Panel and the HSCA medical panel said that the bullet struck 10 cm higher (or 3.9 inches higher), and that the autopsy doctors had committed the mind-boggling blunder of mistaking a wound in the cowlick, clearly above the lambda, for a wound that was 10 cm lower, slightly above the EOP, even though they reflected the scalp and had good reference points for locating the wound (the EOP, the hairline, and the lambda).
Obviously, the entry wound site that you choose will have a huge impact on the trajectory that you try to trace back to the sixth-floor window (SN).
The WC experts said that the EOP entry wound trajected back to the SN. To make the trajectory work, they had to assume that JFK's head was tilted over 50 degrees forward (CE 388). However, the HSCA experts produced two conflicting trajectory analyses. The HSCA medical experts found it necessary to assume a forward head tilt of about 27 degrees, but the HSCA trajectory expert, NASA scientist Tom Canning, said that the head was tilted only about 11 degrees forward. Both of the HSCA analyses assumed that the entry wound was the cowlick site.
Which entry site do you accept? If you accept the cowlick site, you need to face the unsolvable problems with the site. But, if you accept the EOP site, you must believe that the autopsy brain photos are fraudulent, since they categorically rule out the EOP site because they show a virtually undamaged cerebellum and no damage to the rear part of the right occipital lobe. On the other hand, the top-of-head autopsy photos show intact cerebral cortex in/beneath the cowlick site, a physical impossibility if a bullet entered there.
There is an explanation that resolves all of these and other issues, but it means abandoning the lone-gunman fiction. The explanation is that the autopsy brain photos are fraudulent, that the cowlick site is not a bullet wound, that two bullets hit the skull, that one of those two bullets hit the right temple (just as was initially reported by White House press secretary Malcolm Kilduff), and that the back-of-head fragments are ricochet fragments (just as the Clark Panel privately believed). Once you graduate to this realization, (1) the two very different wound paths in the brain--the cortical and subcortical damage--pose no problem; (2) the high fragment trail poses no problem; (3) the undamaged cerebral cortex in/under the cowlick site poses no problem; and (4) the back-of-head fragments pose no problem.