% Poisson process of arrivals A(t) %
S=0; T=0; lambda=0.02;
while S<1000; S=S-1/lambda*log(rand); T=[T S]; end;
N=length(T); time=1:1000; A=zeros(size(time));
for t=1:1000; A(t)=sum(T <= t); end; 
comet(A);