( scratchpad ) :: rcopy ( src dst -- ) src length iota [ [ src nth ] [ dst set-nth ] bi "x" write ] each ; ( scratchpad ) 10 [ 100 iota random ] replicate dup . [ dup length [ insert-sort-at ] with each ] keep . { 19 80 55 25 12 18 8 93 4 90 } xxxxxxxxxxxxxxxxxxxxxxxxxx { 4 8 12 18 19 25 55 80 90 93 } ( scratchpad ) "xxxxxxxxxxxxxxxxxxxxxxxxxx" length . 26