Once upon a time, there were 2 function, G(x) & F(x).
They are very good friend to each other.
G(x)=2x+8
F(x)=(x^2)/4 when -兀<x<兀
and F(x)=F(x+2兀)
But it is very strange that somehow
F(x)=1233211234567 when x= 689
G(x) worried about F(x) very much,
so it asked
"Are you still on your period?"