Try this:
1 -> x
2 -> y
3 -> X
4 -> Y
ClDrw
Line(x,y,X,Y
Disp {x,y,X,Y
This will display {1,0,3,4}
Contens of y variable was destroyed.
Even if y is a list or vector and you draw Line(x,y(1),X,Y
y variable will be destroyed and changed to real type.
Hmm, so many bugs! Should we ask at TI for a free replacement?