Goldberg Variations, BWV 988 - Var. 21 Canone alla Settima (Arranged for Harp by Catrin Finch) (21번 Canone alla Settima (Arranged for Harp by Catrin Finch)|第21変奏 7度のカノン（1段鍵盤）|ダイ２１ヘンソウ)