Ooh nice! I didn't think of that! Since appending to an array is cheap, you can just move-to-end instead of move-to-front, and then iterate in "reverse" order

Ooh nice! I didn't think of that! Since appending to an array is cheap, you can just move-to-end instead of move-to-front, and then iterate in "reverse" order, so from the outside everything seems to Just Work.