n=0:1:6;
x=[1 -5 4 -8 6 -3 -1];
figure(1)
stem(n,x,'linewidth',2)
xlabel('Time index');
ylabel('x(n)');

for m=0:6
    u=mod(m+3,7);
    y1(m+1)=x(u+1);
    u=mod(m-4,7);
    y2(m+1)=x(u+1);
    u=mod(-m+2,7);
    y3(m+1)=x(u+1);
end

figure(2)
stem(n,y1,'linewidth',2)
xlabel('Time index');
ylabel('x(n+3 mod 7)');

figure(3)
stem(n,y2,'linewidth',2)
xlabel('Time index');
ylabel('x(n-4 mod 7)');

figure(4)
stem(n,y3,'linewidth',2)
xlabel('Time index');
ylabel('x(-n+2 mod 7)');