>perl -wMstrict -le
"my $c   = 'A';
 my $min = 3;
 ;;
 my $s = 'uuAvvAAwwAAAxxAAAAyy';
 ;;
 printf qq{'$1' } while $s =~ m{ ([[:lower:]] (?:$c){$min,} [[:lower:]]) }xmsg;
"
'wAAAx' 'xAAAAy'