symbolic n,m;
I1 := {[1,1:n,1:m,0]};
I2 := {[2,1:n,0,0]};
I3 := {[3,1:m,1,1:n]};
I4 := {[3,1:m,2,1:n]};
I5 := {[4,1:m,0,0]};
codegen I1;
codegen I1,I1,I2,I2,I3,I3,I4,I4,I5,I5;