Time to sew darts into the bra front lying on the leaf of the treadle. Remove cat, drop onto floor, examine pattern, go to sewing room to fetch chair. Remove cat, drop onto bed, un-pin pattern, carry pattern into sewing room. Remove cat, throw onto bed, examine the lines faintly marked in easily-removed chalk, go to sewing room for self-removing marking pen. Discover that a human not only can pronounce the Cat word for "I am totally fed up and will now proceed to eat your liver," but will sometimes spontaneously do so.
It didn't stick. Al is now relaxing on the treadle leaf -- but my sewing is in here, waiting for me to clear a spot on the ironing board and press it.