Update:

2 months have passed, and another pup sprouted from the main stalk, this time at the base. This brings the count up to 4 arms that has sprouted from the main stalk, two it's first year and two this year.

There is also the tip cutting that I took from the main stalk, and this is about 8-10 inches tall and rooted pretty well. No pups on this guy yet, but it got planted late in the season so I didn't expect any this year.

The two arms that sprouted last season are now easily a foot long each, if not a couple inches over. They have doubled in size from last year. The two pups from this year are each a couple inches, with 4-5 sets of spines.

These things grow quick. Can't wait for next season when I can take and plant more cuttings.

Happy growing everyone!