This solution is 96 characters, although it orders the results by hour and minute, rather than by year. for$h('00'..'23'){for$m('00'..'59'){print"$h:$m $_/".reverse"\n$h$m $_"for 10,20,30,'01',11,21}} Or, by not worrying about a meaningful order to the results, I can get to 94: for$h('00'..'23'){for$M(102030011121=~/../g){print"$h:$_ $M".reverse"\n$h$_ $M"for'00'..'59'}}