[Moru]

Upward-firing lights are aimed at the roof to spread the light and create more ambient light. So is primarily used as a down-light by reflection anyway.

I'm not sure the left/right shadows are a learned thing from user interfaces. As a kid, long before I got my first computer I was drawing 3D forms. Shadows always was drawn as light came from the upper left.

Maybe this is because I draw with right hand so prefer light to come from the left so I don't shadow my hand?

[hunter2_]

Now you've got me wondering if the left/right shadow preference might actually be rooted in other natural phenomena besides human dominant handedness, like something with the rotation of the earth a.k.a. sun setting in the west.

[hnlmorg]

You're over thinking things there. More likely it's just an artefact of those interfaces being designed in the countries who read left to right.

Off topic but I like how you've referenced that infamous IRC meme in your HN handle.

[mPReDiToR]

What? The username just shows as *_ for me?