How long is a coastline, really?
A distant outline hides bays and small inlets. Before comparing two coastline numbers, ask how each line was drawn.
Look again
Can the same grey look like two different colours?
Two identical squares. Two different surroundings. Your eyes compare more than the patch you are looking at.
Why does the Moon seem to change shape?
The same round Moon can look like a thin crescent or a bright disc. The difference begins with where you are looking from.