In mathematics the differential dx/dt can be written as x dot (ie x with a dot over the top). DBT seems to be making a real hash of this and is making a 2 cell item into something which is 16 cells long It should be x' but it coming out as +,+"?,+]x+,+"?,+ I am attaching a SN file with an example of an x dot in it. I am translating into British code. David Spybey