These fish look strange and deformed from all angels except one where they all look like normal fish. This optical illusion is designed  to be view with the eye or a camera from one angle where all the fish will look normal. 

Instructions:

Print: 1 fish1, 1 fish2, 1 fish3, 3 big stand, 1 small stand, and 1 viewer

either buy 4 10x10mm square rod (I used: https://www.amazon.com/dp/B08Q791V3W?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1) and cut them to 250mm, 230mm, 210mm, and 205mm.

or print rod1, rod2, rod3, and rod_viewer

Print single sided on 11x8.5 paper the alignment_guild and tape together using the coordinate system with 1,1 being in the top left. 

Place the fish where directed on the alignment guild and look through the viewer with one eye open.