If you take a sequence with integers between 0 and 9 (random, say), and run the turtle visualizer with rules only for 0,1,2,3,4 (the default), it will stop as soon as it reaches a sequence value that is not in that range, with no explanation. I don't think this is the desired behaviour. This is an example of invalid parameter inputs that are only defined as invalid on combinations of sequence parameters and visualizer parameters, i.e. won't be checked by either visualizer parameters or sequence parameters alone. I assume the desired behaviour is that the visualizer should handle such things gracefully.
If you take a sequence with integers between 0 and 9 (random, say), and run the turtle visualizer with rules only for 0,1,2,3,4 (the default), it will stop as soon as it reaches a sequence value that is not in that range, with no explanation. I don't think this is the desired behaviour. This is an example of invalid parameter inputs that are only defined as invalid on combinations of sequence parameters and visualizer parameters, i.e. won't be checked by either visualizer parameters or sequence parameters alone. I assume the desired behaviour is that the visualizer should handle such things gracefully.