Rolling billiard balls in a palm

I've got a strange hobby - to roll billiard balls in a palm.

Like these ones:

About 10 years ago a colleague of mine taught me how to roll 2 small metal balls in a palm. This trick interested me so I found some balls from big ball bearing and started my trainings.

Some time later I found myself not satisfied with these small metal ball. I found slightly bigger stone balls and started trainings with them.

At the moment I stuck on billiard balls. They're big enough and pretty easy to find at stores. They also much more robust than stone ones.

Since I wanted to advance in this strange hobby, I started to roll 3 balls at once. I even try to roll 4 of them.



There're some things I'm interested to know -
Where this hobby come from?
What is the history of this skill?
Does it help to my health or whatever else?

love (with processing)

I'm publishing my another experiment with processing.
I called it 'love'
The applet and source code are located here.

How t is done
I wanted my heroes in this sketch to have transparent tails. It is not a problem on solid background. To make tails transparent with bitmap background I used following technique.

1. I render my 'souls' to color layer

a 'man' soul:
a 'woman' soul:

2. I render souls as white spots to other layer. I fade that layer to black before rendering.

3. I add my second layer to the first one as alpha channel 4. I render my background which is a bitmap with some simple animation on it

5. Last step is to render image with 'souls' on top of the background. And then I render some effects 'pink hearts' near pairs which are in love.