: spc 32 ;

: half ( n -- n/2 ) 2 / ;

: rep ( c n -- ) 0 do dup emit loop drop ;

: top ( width -- ) cr dup 3 rot 2 mod - + half spc swap rep '* emit ;

: line ( width index -- )
  cr dup rot 2 + 2 / swap - spc swap rep
  dup 2 * 1+ 0
  do
    dup 3 / i + 4 mod 2 - 0= if '0 emit else '^ emit then
  loop drop ;

: ctree ( width -- )
  page
  dup top
  dup 2 + 2 / 0 do dup i line loop drop
  cr ;

21 ctree bye