public unsafe int PreviousSize(uint id)
 {
     fixed(TetraSize *a = &this)
     return((*&((int *)a)[id]) = PRIMES_ARRAY.Get(--(*&((int *)a)[id + 4])));
 }
 public unsafe int NextSize(uint id)
 {
     fixed(TetraSize *a = &this)
     return((*&((int *)a)[id]) = PRIMES_ARRAY.Get((*&((int *)a)[id + 4])++));
 }