Like a hummingbird.
(Purple-throated Mountain-gem on the left, Coppery-headed Emeralds on the right.)
Or a Great Green Macaw
Emerald Toucanets have different shades of green
(The male is kind of aqua, not quite green and not quite blue.)
And the Emerald Tanager is the same shade as the leaves,but its head is so bright it could have been in the yellow section.