Algodoo

Nice work. Counters matched for over 1000 counts. If you are interested in the speed of rolling balls, then check out the Brachistochrone and Tautochrone curves.

Waw, 1000 counts is a good result.
As always, thank you !!
I will make a video on the Brachistochrone curve !!

I modified the scene as follows:
1. Select all the balls.
2. Check "No self collision".
3. Set all radii to 0.2.
4. Scale the textures to fit each ball.

In the laser:
_eID1 := 0;
onSpawn := (e)=>{
_eID = 0;
_eID1 = 0;
};
onLaserHit := (e)=>{
eID := e.geom.entityID;
eID != _eID && eID != _eID1 ? {
my.scene.hits3 = my.scene.hits3 + 1;
_eID1 = _eID;
_eID = eID
} : {}
};

Now the laser is able to count balls that don't collide with each other. I tested this and got 1 error in 1250 counts.

See The Brachistochrone to see how to create a cycloid curve in Algodoo.

Here is a way to create a cycloid curve:
1. Start with the default scene (just (1) plane).
2. Create a 1.0 radius circle that contacts the plane.
3. Create a 0.125 radius circle at the ball to plane contact point.
4. Uncheck all collision layers for the small circle.
5. Select both circles and glue together.
6. Put angVel = 0.5 in the big circle's postStep event.
7. Set the big circle and plane collision layer to B only.
8. Set Selection>Follow for the small circle.
9. Set brush size to 0.25.
10. Turn off the grid.
11. Position the brush tool directly over the small ball.
12. Hold down the left mouse button.
13. Press the space bar to start the scene.
14. Stop the scene and raise the mouse button when the small circle center is directly under the big circle center.
15. The polygon produced is the path of a rolling 0.25 cylinder whose center of mass traces out a cycloid. This is the solution for the Brachistochrone of a rolling object.
16. Rotate the polygon 180°.
17. Subtract the polygon from a rectangle to create the correct curve.
18. Glue the curve to the background.

WOW !! Very interesting!!
Fantastic makeup.
Thanks!!!
I had done it in a much less direct way.
I drew the curve with the tracer, then a screenshot.
I cut the curve with an image editor and imported it on Algodoo ....