anchor.diff:  
       (bench-pmatrix-mul
        (matrix-mul pmatrix-mul)
  -     (10 50 100 200)
  +     (5 10 50 100 200)
        ,*trials*
        ,*rehearsals*)))
   
  
positive.code: (defparameter *benches*
    `((bench-pmap
       (map pmap)
       (10 100 500 1000 5000 10000 50000 100000 500000)
       ,*trials*
       ,*rehearsals*)
  
      (bench-psort
       (sort psort)
  
negative.code:   (declare (optimize (speed 3) (safety 0) (debug 0)))
    (if (< n 2)
        n
        (plet-if (> n 15)
            ((a (fib-plet-if (- n 1)))
             (b (fib-plet-if (- n 2))))
          (+ a b))))
  