set G_ = make lcg with -41,50,43,5005. 
set G_ span to -5000.05,5001.05. 

#set G = make lcgv3 with 50.1,4545,11,G_,-50001,50000.05,1,1. 
set G = make lcgv3 with 99,23,-133,-1000,1000,G_,-500,500.5,1,1. 
set G2 = make lcgv3 with 99,23,-133,-1000,1000,G_,-500,500,1,1. 
#set G2 = make lcgv3 with -19,23,-133,-1000,1000,G_,-500,500,1,1. 
#set G3 = make lcgv3 with 27,-13,-90,-1000,1000,G_,-500,500,1,1. 

set O = make op2 with +,-,0.75. 
set G4 = merge G_,G_ with +.
set G5 = merge G4,G_ with O. 
set G6 = merge G_,G5,G_ with -,O. 
set G7 = merge G4,G6 with /.

set O2 = make op2 with *,/,0.4. 
set G8 = merge G7,G5 with O2. 
set G9 = merge G7,G5,G4,G6,G7 to tree. 

set F = open file f2xx.txt for seq. 
write G9 for 2000 iter to F.