module SortCell(int ?x_in,?y_in,!x_out,!y_out) {
    loop {
        if(y_in<x_in) {
            next(y_out) = y_in;
            next(x_out) = x_in;
        } else {
            next(y_out) = x_in;
            next(x_out) = y_in;
        }
        pause;
    }
}