Question: Help! My plots are being converted to ASCII art!

I opened one of my worksheets this morning and started executing it using the ! tool. When it came to the first plot command, it replaced the previous plotted output by the following:

1 ************                                                                
  +          **********                                                       
  +                   ******                                                  
  +                         *****A                                            
  +                             BB***A                                        
0.5                                  B***A                                    
  +                                     BB**AA                                
  +                                         BB*AAA                            
  +                                            BBBAAAA                        
  +                                              BBB  AAA                     
  |                                                 BBB  AAAA                 
  ++-++-++-++-++-++-++-++-++-++-++-++-+++-++-++-++-++-****+-+***+-++-++-++-++ 
0 +     0.2     0.4    0.6     0.8     1     1.2     1.4 BBB1.6 AAAA1.8     2 
  +                                                         BB      AAAA      
  +                                                          BBB       AAAA   
  +                                                             BB         AA 
-0.5                                                              BBB         
  +                                                                 BB        
  +                                                                   BB      
  +                                                                     BB    
  +                                                                       BB  
-1+                                                                         B 
                                                                            

This would have been very impressive in 1975, but it isn't so great in 2011. All successive plots are being rendered similarly. I certainly didn't switch this on on purpose. How can I switch it off? And why on earth does Maple 13 still include this obsolete code?

Lawrence Paulson, University of Cambridge