Glide
Sprites sliding to a new place with glide() instead of jumping there. Hold the
mouse down and the alien glides to it over one second; the coin glides between
two corners for as long as the program runs.
glide() does not hold the sprite up, so run() keeps being called while it is
on its way. isGliding() says whether it has arrived, which is how the coin
knows to turn around:
public void run() {
if (this.isGliding()) {
return;
}
this.glide(2, 220, 140);
}