Here is the starter after 23 hours:
Not much different than the 17 hour picture, just wanted to get it before I added the 2/3 gallon of additional wort.
Here it is after the addition:
Looking darker again with all the extra wort.
After 36 hours, 12 hours with fresh wort and nutrient added:
With all that yeast in there, it really took off with the fresh wort. I didn't notice much of a krausen when making starters on a stir plate before, but there is definitely one this time. The stir plate seems to keep the krausen broken up but this is really bubbling.
Close up of krausen, can see the bubbles rising to the top quickly, looks like a milky gallon of soda: