function [p1,p2] = position2(p1,p2)

    d = rand;
    if d<=0.25 
        p1 = p1-6;
    elseif d>0.25 & d <=0.5
        p1 = p1 + 6;
    elseif d>0.5 & d <=0.75
        p2 = p2-6;
    else
        p2 = p2+6;
    end