When generating graphs and showing different sets of data it usually a good idea to difference the sets by color. So one line is red and the next is green and so on. The pro
You could get a random set of your 3 255 values and check it against the last set of 3 values, making sure they are each at least X away from the old values before using them.
OLD: 190, 120, 100
NEW: 180, 200, 30
If X = 20, then the new set would be regenerated again.