Note:
The file Manta_ray_atractor.pdf
is supposed to run some videos in page 17,
but with most browsers you will not be able to see them.

If this is the case, download Manta_ray_atractor.pdf and TheVideos.zip.
Then open the zip file and place both
Manta_ray_atractor.pdf
TheVideos
in the same directory. Then you should be able to see the videos if you
open Manta_ray_atractor.pdf with Adobe [Adobe will ask you if you trust
Manta_ray_atractor.pdf, to allow it to run the videos].

If this still does not work, you can open the videos directly.
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