"!"
"     ___    !"
"    /...\   !"
"   /.=.=.\  !"
"   |_____|  !"
"   _/ | \_  !"
"            !"
"Lunar Lander!"
"!"

1000  F:   ~Fuel
100   A:   ~Altitude
100   R:   ~Range
0     I:   ~Horizontal Velocity
0     J:   ~Vertical Velocity
0 3 - G:   ~Gravity

(
   "!"
   "### Alt=" A.! " Range=" R.! " Fuel=" F.!
   " HV=" I.! " VV=" J.! " Grav=" G.! " ###!"

   F.                      ~if there is fuel left
   [
      "Horizontal Thrust? "
      ? H:
      "Vertical Thrust? "
      ? V:
   ]
   F. 0 =                  ~if out of fuel
   [
      "Out of fuel.!"      ~then no thrust
      0 H:
      0 V:
   ]
   I. H. + I:              ~Horizontal Accel
   J. G. + V. + J:         ~Vertical Accel
   A. J. + A:              ~Adjust Altitude
   R. I. + R:              ~Adjust Range
                           ~take abs val of h and v
   H. 0 <                  ~if h < 0
   [
      0 H. - H:            ~then h = - h
   ]
   V. 0 <                  ~if v < 0
   [
      0 V. - V:            ~then v = -v
   ]
   F. V. H. - - F:         ~fuel = fuel - v - h
   A. 0 <                  ~if altitude < 0
   [
      "!!### You landed with!"
      "a horizontal velocity of " I.! "!"
      "a vertical velocity of " J.! "!"
      R.! " meters from the landing pad.!"
      0 ^
   ]
)
$