So much for a loose, rapid sketch. I started this one several times, as I would put in the back and not leave enough room for the legs. I reversed that situation by starting with the legs and not leaving enough from for the back. Consistent in my efforts, that’s for sure.
A bit wobbly, perhaps
Italian, Florence, 1489-1491
Sketch 049: Chair (Sgabello), Metropolitan Museum of Art, Fletcher Fund, 1930
It's a long story ... 
Looks like you finally fit everything in. š