Mystery solved!

Sitting at my Brother sewing machine the other day...I noticed several (like 4) empty spools of thread....?????)  Didn't  think much of it.  The next day I noticed that the roomba was marooned under the Pfaff's sewing machine table hung up on the rheostat cord.  WHOA, I don't recall hearing roomba clearing in the sewing room.  Today I figured it was time to put roomba back into his dock in the living room.  It was as I was disentangling him fromthe rheostat cord that I noticed all this thread wrapped around various and sundry parts of his undercarriage.  (sigh).  My thought was that it is like having a mischievous cat in the house.  OH, WAIT A MINUTES, now I know why there were all these empty spools of thread.  Know all the pictures you've seen with a cat sitting in a HUGE pile of toilet tissue??  Naughty Roomba!!!!  Now I know why they suggest you do not have a roomba run when you aren't at home.  Now I know why.