1 { 10 * } 70 times constant One
{ bl word (number) dup 0= abort"invalid fixed-point constant"  
  1- { One swap */r } { One * } cond 1 'nop } ::_ F$
' + : F+
' - : F-
{ One */r } : F*
{ One swap */r } : F/
{ One dup rot */r } : Finv
{ One { 2dup F/ F+ 2/ } 9 times nip } : Fsqrt
{ ' Fsqrt 128 times One F- 128 << } : Fln
{ dup abs <# ' # 70 times char . hold #s rot sign #>
  nip -trailing0 type space } : .F
F$17/12 .F
F$3.14159265 .F
{ 1 0 rot { -rot over + swap rot 2dup >= } until drop
} : fib-gtr
One fib-gtr F/ .F
F$2 Fsqrt .F
F$2 Fln .F