How can I get a simple function I want in Simulink? The details are included.

The original values are from a simple function f(t+1)=f(t)+1

Now what I want is, if f(t)>7,f(t)=f(t-1)-0.4, and this function should be maintained for 3 seconds (3 times). After three seconds, the function will be again be f(t+1)=f(t)+1.

So how could I realise this in Simulink?

The results should be the same as the figure shown.

I appreciate your replies. Cheers!