4 items of trick photography are in this photo, a 1930 Popular Science game. Nov 1930 issue

Considering that it's not likely for us to even know what they are doing with the other things in the image, just 80 years later, I doubt anyone will spot the 4 pieces of trick photography that are things in the wrong places or somehow not correct for the scene.

A lot has changed in 80 years, they could be referring to the type of shoes commonly used, or the fact that the guy is kneeling wrong for a left handed guy. Who knows... it's possible that they messed with something like the garage doors in a way that we wouldn't understand... like maybe back in the 30s the left door always went in front when slid open, and the right hand door ought to be in back.

Or maybe they meant that a car of that make and model would have gas headlights, and should have the Calcium Carbonate storage on the passenger side of the car, on the running board, instead of the drivers side.

History. Lots of common things have been lost.

I think I've found 3 things they messed with in the photo though

Nov 1930 Popular Science monthly

December 1930 Popular Science