how to make Δ in matlab simulink block diagram

now i'm working on the wind simulation program. but, i need to make math equation by using delta( the difference between first and second of the same output). i don't know how to make it using this matlab simulink block diagram.

Answer 1

[Walter Roberson]

split the output, send one copy to a unit delay, send the other copy and the output of the unit delay to a subtractor ?