green yard lizards have necks that expand and turn rosy red when they
are seeking a mate. 'Come hither!' the bright splash of swelling color
seems to say. Fireflies (a.k.a. lightning bugs) have bodies that blink
brightly in the night. 'Here I am!' they seem to say. People have faces
that turn rosy with interest and shyness. The pupils of their eyes
dilate. 'Umm. Do you like me?' their faces seem to say. Frogs croak over
and over: 'Come find me! I'm at the pond!'