I always enjoy the Google doodles.
The Earth Day doodle is even nicer to watch & play with,
if you left-click on "View" on the menu,
and then choose "Zoom" and increase it to whatever size best fits your monitor.
The following website describes all the features of this amazing animation.
I only quoted a little of the article which also has 2 screenprints showing
changes in the doodle. It tells you what to click on to get some of the features to start.
Google's Earth Day doodle reflects planet's complexity
To mark the 43rd Earth Day, Google produces one of its busiest -- but still subtle -- animated doodles, depicting our planet's ever-changing landscape.
by Steven Musil
April 21, 2013 10:54 PM PDT
"Today we are celebrating Earth Day with an interactive doodle that captures a slice of nature's subtle wonders," doodler Leon Hong wrote.
"We hope you enjoy discovering animals, controlling the weather, and observing the seasons."
Clicking on the Sun/start button over the mountains sets the landscape and seasons in motion.
The sun will set, replaced by the light of the rotating moon.
In fact, the doodle presents us with all phases of the moon: full, half, crescent, and gibbous.
And with each dawn, we are presented with another season, beginning in spring and cycling into summer, fall, and winter before its eventual return to spring, where, like on terra firma, the cycle repeats itself.
Like many previous doodles, the Earth Day doodle is interactive.
Clicking on the clouds will produce snow in the winter and rain in the other seasons.
Mousing over the logo will produce a gentle breeze that obliterates the G before nature allows it to regenerate.
The doodle also has its share of resident wildlife that users can interact with: birds inhabit the sky, fish swim in the lake, a bear resides in a cave, ants scurry near the G flowers, and fireflies appear at night after a gentle rain.