[Retros] Die Schwalbe Heft 224: correction to #13336

[Valery Liskovets]

The triplet (c) in my problem #13336 has, unfortunately,
an unintentional solution. Correction: (c)=(b) & bPe7->d6
(instead, stipulated "2 solutions" in the published version
of (c) would also make sense).

Valery Liskovets