this is abc1's new account, also it work like this, red's onCollide = (e)=>{e.other.materialName == "marble" ? {e.other.color = color; e.other.onCollide = onCollide} : {}}
so, the e.other.materialName == "marble" ? {} : {} use to check if the object it touch's materialName is "marble" if it is, it'll do what the first {} tell, in this case, the first {} tell e.other.color = color; e.other.onCollide = onCollide
the e.other.color = color is changing the object touch's color to be same as its color, and the e.other.onCollide = on.Collide use to change the object it touch's onCollide script to be the same as its onCollide script
