10MODE7
   20VDU 26
   30Lines=13 :REM 2,4 interesting too...
   40VDU 28,0,Lines-1,39,0
   50PROCC(11,15) : PROCC(10,&2) :REM Block cursor noblink
   60PROCC(5,8) : REM Down screen a tad
   70PROCC(6,Lines) :REM Displayed lines
   80PROCC(4,Lines+1) :REM Lnes+1 => Flyback point 
   90PROCC(0,127) :REM DOUBLE HEIGHT!!
  100PROCC(7,Lines): REM vert synch in rows
  110END
  120DEFPROCZ
  130PROCT(0)
  140VP=VPOS
  150VDU 26 :REM undo window
  160VDU 31,0,VP
  170PROCC(0,63)
  180PROCC(6,25)
  190PROCC(5,0)
  200PROCC(4,30)
  210PROCC(7,27)
  220ENDPROC
  230DEFPROCC(R,V)
  240VDU 23,0,R,V,0,0,0,0,0,0
  250ENDPROC
  260DEFPROCD(R,L,U,S)
  270FOR I=L TO U STEP S
  280VDU 31,4,1:PRINTI
  290PROCC(R,I)
  300C=GET
  310NEXT
  320ENDPROC
  330DEFPROCT(half)
  340A%=&A0:X%=&50
  350PYXA%=USR(&FFF4)
  360PYXA%=PYXA% AND &FFFF00
  370PYXA%=PYXA% DIV 256
  380IF half=0 THEN Ad=PYXA%
  390IF half=1 THEN Ad=PYXA%+12*40
  400Ad=Ad-&7400
  410Ad=Ad EOR &2000
  420PROCC(12,Ad DIV 256)
  430PROCC(13,Ad MOD 256)
  440ENDPROC
  450DEFPROCA
  460VDU 26
  470VDU 28,0,12,39,0
  480PROCT(0)
  490ENDPROC
  500DEFPROCB
  510VDU 26
  520VDU 28,0,24,39,12
  530PROCT(1)
  540ENDPROC