@Don McErlean posted:
....Here is the Marx Monon FM diesel "B" unit, 8 wheel variety. This really shows the Marx art of lithography, note the use of shadows in the portholes, hatch doors, and vents to give the illusion of depth, the car side is in fact completely flat.
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Finally the end view. I am really impressed with the shadow effect for the end doors. They look remarkably 3-dimensional and when you look at the item, you would swear that they in fact are openings in the side. They are not, the doors are completely 2 dimensional and flat. The optical illusion is really well done.
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Thanks for posting this. Although I have the 4-wheel version, I'm ashamed to admit that I never noticed the shading on the doors. It's a really nice effect on an inexpensive toy train.