-> SUB TWIST2 (DI) 
 
->   ; this one'll work in colour too. 
 
->   LINE (79, 0)-(79, 479)    ') These lines, plus top and bottom of 
->   LINE (561, 0)-(561, 479)  ') screen, outline the square 
->   IF DI THEN 
 
->   FOR C = 0 TO 239 
->   FOR O = -C TO C 
 
->   w = POINT(319 - C, 240 + O) 
->   x = POINT(319 - O, 239 - C) 
->   y = POINT(320 + C, 239 - O) 
->   z = POINT(320 + O, 240 + C) 
 
->   PSET (319 - C, 240 + O), z 
->   PSET (319 - O, 239 - C), w 
->   PSET (320 + C, 239 - O), x 
->   PSET (320 + O, 240 + C), y 
 
-> NEXT 
-> NEXT 
-> ELSE 
 
->   FOR C = 0 TO 239 
->   FOR O = -C TO C 
 
->   w = POINT(319 - C, 240 + O) 
->   x = POINT(319 - O, 239 - C) 
->   y = POINT(320 + C, 239 - O) 
->   z = POINT(320 + O, 240 + C) 
 
->   PSET (319 - C, 240 + O), x 
->   PSET (319 - O, 239 - C), y 
->   PSET (320 + C, 239 - O), z 
->   PSET (320 + O, 240 + C), w 
 
->   NEXT 
->   NEXT 
 
-> END IF 
-> END SUB 
  
I haven't tried it, but won't this over-write itself? It looks to me 
like the rotated image will be superimposed over the original one. My 
routine BSAVEs the screen to disk, then does a CLS before reading the 
disk file and using it to write the rotated image to the screen. 
  
Also, your routine looks like it will be very slow. But I'll try it 
when I get a chance. 
  
                            dw 
--- Platinum Xpress/Win/WINServer v3.0pr5