Non-conditional Loop
A B C D
1 0      
2 for    
3   >A1=A1+#A2  
4   if #A2==100 break
5 0      
6 for    
7   >B5=#A6  
8   >A5=A5+B5  
9   if A5>=1000 break

After executing, the result of A1 is as follows:

Of A5 the result is as follows:

Of B5 the result is as follows: