function r=lifeordeath(x1,y1,x0,y0)
%This file computes the number of illumatons.
%that arrive at the point (x1,y1), assuming the death,
%ray strikes 1 meter above the point (x0,y0).
%If that number exceeds 100,a "1" is returned in the 
%variable "r"; otherwise a "0" is returned for "r".
dosage=10000/(4*pi*((x1-x0)^2 + (y1-y0)^2 + 1));
if dosage>50
    r=1;
else
    r=0;
end