Amazing Query ! Try It

select decode 
        ( sign(floor(MaxWidth /2)-rownum) 
        , 1 
        , lpad( ' ', floor(MaxWidth /2)-(rownum-1)) || rpad( '*', 2*(rownum-1)+1, ' *') 
        , lpad( '* * *', floor(MaxWidth/2)+3)
        ) 
  from all_tables , (select 60 as MaxWidth from dual) Mx 
where rownum < floor(MaxWidth /2) + 6;