Using my loaf

Today's bake turned out so well I took a picture of it on the wall outside.
Then I noticed something I have seen in other photographs of objects taken from above. The slashes I had made to allow the loaf to expand in the oven sometimes appeared raised rather than depressed,  convex instead of concave. Do you see what I mean?

I've been aware of this phenomenon before so I decide to find out about it. Seems it's to do with the way shadows fall. Our eyes are accustomed to see everything with the sun as the main light source and it invariably  travels from east to west. It never shines from the north.  So when we see an image lit from that side (top right hand corner) our eyes convert it according to expectation. That means on a relief map we may see mountains where there are actually valleys unless an adjustment is built in by the cartographers.

If you have a few minutes to spare this is explained much more clearly in a short video here.