Parametric Function with SIMULINK block or Matlab Code

Need help to plot a parametric function with these following conditions in Matlab or SIMULINK Where x is the input and u is the output When x(t)={-1 -----------------------> x(t)<-1 {x(t-1)+u(t) --------------> -1 =< x(t) =< 1 {1 ------------------------> x(t)>1