This visualisation represents the simplest form of the innovation model
introduced in
Scientific Reports 4, 5890 (2014).
An urn initially contains a red ball.
At each time step a ball is randomly extracted with equal probability from the urn.
Its color is registered in the stream, whose histogram is here represented as a pie chart.
If that color was never observed before, i.e. it is not yet present in the stream,
nu+1 balls with each a brand new color, are added into the urn thus building
the "adjacent possible".
Independently, rho exact copies of the extracted ball are added to the urn.
The randomly chosen ball is the pulsing one; the balls with brand new colors
enter the scene from the right side of the simulation; the copies of the balls
with an already observed color enter from the left side.