I guess the computer decided I'd been using it too much! It's a Janome Horizon that I got this past summer -- my big splurge for the year ... or decade!. The screen goes to "E4" shortly after powering on. Dealer says he has to replace a board. I've seen some other posts regarding similar failures. I don't think it overheated, although I had been doing some heavy monogramming right before it died.
On my wreath, I quilted about 1/4 inside the edges of each of the wheels. Then I did a close stipple with swirls in the white background.