question: If all trains have a reddish front, and no image shows the front of more than one train.
#1 return trains 
#2 return front  of #1 
#3 return #1 where  #2 is reddish 
#4 return number of  #1 
#5 return number of  #3 
#6 return if  #4 is equal to  #5 
#7 return images 
#8 return number of  #2 for each  #7 
#9 return #7 where  #8 is higher than one 
#10 return number of  #9 
#11 return if  #10 is equal to  zero 
#12 return if  both  #6 and #11 are true