Do you want a function that plays on both sides of the x and y axis?
This function will shock you running closely along the y and x- axis but never ever touching or crossing them. The parent function featured above f(x)= 1/x. No matter the numbers in the function it will never cross the axis' unless you tell it to, and will do exactly as you tell it to. Is it a little odd? yes. But I bet you like it that way don't you.
Shia LaBeouf "Just Do It" Motivational Speech (Original Video)