Algodoo

An improved version of the old 'Time Control' scene.
Now, after playing the scene for a short time, you can click the 'Playback' button to see an "instant replay" of the green box.
You can also adjust the time scale of the replay by editing the text in the blue box on the right (Input a negative value to play the recording in reverse.).
There is also a 'Loop Playback' option, which determines whether or not the replay loops indefinitely.
(The old description that follows still applies.)

Old Description:

A scene where you can reverse the green box's flow of time by holding the 'y' key.
The anchor represents the reference point from which the object is recorded and
then replayed in reverse when the key is held.
Also, inside the black panels is the code used, plus some other functions.