modulation of binary sequence

I would like to replace the bits of 1s and 0s with the signal made with different phase of 90 degrees

 if true
    % clear;
clc;
number_bits=4;
sequence=randi([0 1],1,number_bits);
fs=1e4;
f=1e3;
t=0:(1/fs):0.01;
signal=sin(2*pi*f*t);
message=[]
figure;
plot(t,signal);
grid on;
title('Continous wave signal');
for i=1:number_bits
    if sequence(i)==0
        sig=zeros(1,length(t));
    else sig=signal;
    end
    figure;
    plot(t,sig);
    grid on;
    hold on;
    message=[message sig];
end
message
t_message=0:1/fs:0.01*4;
figure
plot(t_message,message)
  end