[Falcor]

Well something simple like this shouldn't require much thought. You wanna take a value (.4) and make it into 0 gradually. lets think now. How can we do this with the for operative? I know we can start out at .4 and then subtract .04 while it is greater than or equal to 0!!
for(this.i=.4;this.i>=0;this.i-=0.04)


now you have this.i moving down .04 every time it loops... figure out the rest.