Algodoo

Angle is in units of Radians, not degrees. The scene seems to work, but it's not flipping heads and tails every 180 degrees as you probably thought it would, based on your code.

can you give me a scene example?

Stick an axle in the middle of your coin, and make it rotate slowly. You will see that the coin doesn't flip every 180 degrees. If you want to use degrees, the conversion is Deg = Rads * 180/pi.

This works:
{
angle > math.pi ? {scene.my.tails = 1} : {};
angle > 0 ? {scene.my.tails = 0} : {};
1.0
}

Since there are 2pi radians in 360 degrees, this flips each time the angle changes positive and negative with each rotation.

actually, this is simpler and it works just as well:
{
angle < 0 ? {scene.my.tails = 1} : {};
angle > 0 ? {scene.my.tails = 0} : {};
1.0
}

It works because in Algodoo, a complete rotation goes from zero to +pi (3.14) in the first 180 degrees, and -pi (-3.14) in the second 180 degrees, back to zero. So, you only need to check if the angle is positive or negative in order to make something happen twice per rotation!

EDIT: After thinking about it, I realized that the script can be made even simpler!

{
angle < 0 ? {scene.my.tails = 1} : {scene.my.tails = 0};
1.0
}

Shoud you do phun for tails?