perl -Mstrict -Mwarnings -E 'my $WIDTH = 50; my ( $try, $i, $j ) = (0) x 3; for ( 1 .. 40 ) { ++$try; my $rand = `perl -E "say rand()"`; $rand < .5 ? ++$i : ++$j; printf qq[%${WIDTH}s : %s\n], "#" x ( $i * $WIDTH / $try ), "#" x ( $j * $WIDTH / $try ); }'