anchor.diff:  \   reverse2
     key? until ;
   
  +: pen-up    500  50 0 do 10 + dup PEN pwm 10 ms loop  drop ;
  +: pen-down 1000  50 0 do 10 - dup PEN pwm 10 ms loop  drop ;
  +
  +: pen-cycle
  +  500  begin
  +    pen-down
  +    LED ioc!  1000 ms  LED ios!
  +    pen-up
  +    500 ms
  +  key? until  drop ;
  +
   app-setup
  
positive.code: PA7 constant M2D
  
  : app-setup
    OMODE-PP LED io-mode!
    OMODE-PP M1A io-mode!
    OMODE-PP M1B io-mode!
    OMODE-PP M1C io-mode!
  
negative.code: forgetram
  
  PC13 constant LED
  
  PB0 constant PEN
  
  PA0 constant M1A
  PA1 constant M1B
  