Four integers are marked on a circle. On each step we simultaneously replace each number by the difference between this number and next number on the circle, moving in a clockwise direction; that is, the numbers
![a,b,c,d](/media/m/7/6/0/7605ede133e1f767d3890e0bfffb7b7f.png)
are replaced by
![a-b,b-c,c-d,d-a.](/media/m/3/d/a/3da13246e58ea772c2afd08f622748e1.png)
Is it possible after 1996 such to have numbers
![a,b,c,d](/media/m/7/6/0/7605ede133e1f767d3890e0bfffb7b7f.png)
such the numbers
![|bc-ad|, |ac - bd|, |ab - cd|](/media/m/d/8/a/d8ae527740617e0870746a338ba1243f.png)
are primes?
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Four integers are marked on a circle. On each step we simultaneously replace each number by the difference between this number and next number on the circle, moving in a clockwise direction; that is, the numbers $a,b,c,d$ are replaced by $a-b,b-c,c-d,d-a.$ Is it possible after 1996 such to have numbers $a,b,c,d$ such the numbers $|bc-ad|, |ac - bd|, |ab - cd|$ are primes?