Plot +1 -1 -1 +1 and -1 +1 +1 -1 rectangular pulse

I would like to ask for advice to help me to plot the rectangular pulse having +1 -1 -1 +1 and -1 +1 +1 -1 in amplitude. Before, I plot with +1 -1 +1 -1 and +1 +1 -1 -1, and I managed to do it. Can anyone please advice me on this? Below is my code;

for m = 0:Npulses
    if  rem(m,2) == 0 %i is even
        Tx1 = exp(1j*pi*gamma*(t-m*PRI).^2);
        W=ones(size(t));
        W(t<m*PRI)=0; 
        W(t>(m*PRI+tau))=0; 
        s1 = Tx1.*W+s1;
      else
          Tx2 = -exp(1j*pi*gamma*(t-m*PRI).^2);%
          W=ones(size(t));
          W(t<m*PRI)=0;
          W(t>(m*PRI+tau))=0;
          s1 = Tx2.*W+s1;
    end

where Npulses is number of pulses and PRI is Pulse Repetitive Interval.