Diamonds of Same Colour

Diamonds on the top is more darker then those of bottom diamonds?

shaded diamonds

No, you are wrong (if you assume, those crazy diamonds are of different color, ha ha) ..... All diamonds are identical, but it sure doesn't look like it.

The key is that the diamonds are shaded so they are slightly lighter at the top and darker at the bottom. That way, when you put them together on the paper in rows, it looks like the rows are different. [source]

Flower Vase or Pair of Face

Two faces hides in the flower vase!

is it a vase or are there two faces looking at each other?

Both the background and foreground are equally strong, so this figure tends to pop in and out. First you see just a vase, then it’s just a pair of faces.

Vase Illusion :

In the same time looks like some sort of vase, as well as two heads facing each other.

Also Watch :
Rubin's Vase