The title refers to remarks linked to this afternoon :

"An ingenious story line serves to convey
the mysteriousness of destiny, the 'grim pen'
of fate that encloses Hazel Shade."

— John Burt Foster Jr. on page 224 of
Nabokov's Art of Memory and European Modernism
(Princeton University Press, 1993)

IMAGE- Instances of 'grimpen' in 'Nabokov's Art of Memory'

Vide  a relevant page on Wallace Stevens.