Oh the frustration of not having a camera.
Before we left for Chicago (March 6), I had 3 potatoes in my cabinet (cool, dark place, y'know). When I came back, they had sprouted. A lot. I decided to leave them there for a while longer to see what would happen.
The 2 Yukon golds, about 3 inches long, now have 4-inch sprouts.
The red potato, about 5 inches long, has sprouts coming from 3 places, each with a multitude of arms. The biggest sprout has about 12 arms. Picture a sea anemone attached to a potato.